TWI458589B - Profile measuring method - Google Patents

Description

Contour measurement method

The present invention relates to a method and apparatus for trimming a polishing pad on a polishing table by pressing a trimmer against a polishing pad. The present invention also relates to a method for measuring a profile of a polishing pad, and polishing of a substrate. A device, and a method of polishing a substrate.

Recent advances in semiconductor component high integration technology have resulted in smaller wiring patterns and narrower distances between interconnects. Photolithography is one step in the component process. Steppers in photolithography require a very flat image plane, especially when making interconnects up to 0.5 μm wide, because the depth of focus is small. Therefore, a polishing apparatus that performs chemical mechanical polishing (CMP) is used to planarize the surface of the semiconductor wafer.

Conventionally, as shown in FIG. 1, the polishing apparatus of this type generally comprises: a polishing table 102 on which a polishing pad (or a polishing cloth) 100 for providing an abrasive surface is held; a top ring 104 for The substrate (for example, a semiconductor wafer) W, that is, the workpiece to be polished, is held. The top ring 104 rotates the substrate W and presses the substrate W against the polishing pad 100 on the rotating polishing table 102 at a fixed pressure, while the nozzle 106 supplies the polishing liquid onto the polishing pad 100, thereby The surface of the substrate W is polished to a flat mirror surface. Examples of the polishing liquid that can be used include an alkaline solution in which abrasive grains are suspended, and abrasive particles such as cerium oxide particles. By using such a polishing liquid, the substrate W is chemically and mechanically ground by a combination of chemical polishing of an alkaline solution and mechanical grinding of abrasive grains.

The polishing apparatus also has a finishing device disposed adjacent to the polishing table 102. The dressing device includes a finisher 108 for repairing the abrasive surface of the polishing pad 100 that has deteriorated through the grinding process. The dresser 108 is configured to rotate with its own axis and will have its trim surface contact the abrasive surface of the polishing pad 100 on the rotating polishing table 102, thereby removing the polishing liquid on the polishing surface and breaking The chips are capable of planarizing and trimming the abrasive surface of the polishing pad 100. A diamond trimmer is typically employed as the trimmer 108 to wipe and planarize the abrasive surface of the polishing pad 100. The uniformity of the polished surface after trimming will have a great influence on the grinding accuracy during the subsequent substrate grinding process.

When the dresser 108 is replaced with a new dresser, the following problems occur. Because of the different properties of individual trimmers, new trimmers may have different cutting pad cutting rates. As a result, the removal rate and the grinding profile may also change. After the dresser 108 is replaced with a new finisher, the new dresser is typically pre-treated with a specified pressure to apply pressure to the polishing pad 100. However, the process of pretreatment is very troublesome because it may have an adverse effect on the polishing performance at the beginning of the grinding of the substrate W. In addition, the slurry removed during the trimming process may be firmly deposited on the dresser 108, which is detrimental to the stability of the polishing performance.

The object of the present invention is to provide a dressing method and a trimming device, which can keep the newly replaced dresser at a certain polishing pad cutting rate; and can avoid the removal rate and the grinding profile change due to individual trimmers having different properties; Handling the newly installed dresser without adversely affecting the polishing pad; and avoiding the deposition of solid thick slurry on the dresser. Another object of the present invention is to provide a profile measurement method. Still another object of the present invention is to provide a substrate polishing apparatus and a substrate polishing method which are capable of determining a polishing pad profile from a cutting rate measured by a dresser. Still another object of the present invention is to provide a substrate polishing apparatus and a substrate polishing method capable of polishing a substrate in accordance with a contour of a polishing pad.

In order to solve the above drawbacks, one of the aspects of the present invention proposes a method for measuring the profile of a polishing pad that has been trimmed by a dresser under predetermined finishing conditions. The method includes repeatedly moving a trimmer on an upper surface of the polishing pad toward a radial direction of the polishing pad to perform a trimming process on the polishing pad; during the trimming process, measuring a plurality of regions on the polishing surface The height of the upper surface of the polishing pad at a predetermined point, and the plurality of regions are arranged along the radial direction of the polishing pad; repeating the repeated movement of the trimmer and measuring the height of the upper surface of the polishing pad for measurement The height of the upper surface of the polishing pad in all areas.

According to the invention as described above, the profile of the polishing pad can be measured without using an expensive high performance data processing device.

In a preferred aspect of the invention, the method further comprises repeatedly performing repeated movements of the trimmer and measuring the height of the upper surface of the polishing pad to obtain measurements of individual regions and calculating an average from the measured values, each The average values represent the upper surface heights in the various regions.

According to the invention as described above, the contour of the polishing pad can be accurately measured.

Another aspect of the invention proposes a method for trimming a polishing pad located on a polishing table. The method includes: trimming the polishing pad by applying a trimming force against the polishing pad under predetermined finishing conditions; measuring a cutting rate of the polishing pad; and feeding back the cutting rate to a predetermined finishing condition.

According to the foregoing invention, the cutting rate of the polishing pad can be maintained even if a new dresser is replaced. Therefore, it is possible to avoid variations in the removal rate and the profile of the grinding due to the different properties of the individual dressers.

Another aspect of the present invention provides a finishing device for trimming a polishing pad located on a polishing table. The apparatus includes: a trimmer configured to trim the polishing pad by applying pressure to the polishing pad under predetermined conditioning conditions; the trimmer operating controller is configured to control the operation of the trimmer and establish a predetermined a trimming condition; and a cutting rate measuring section configured to measure a cutting rate of the polishing pad and to feed back the measured cutting rate to the trimmer operation controller. The trimmer operation controller is configured to reflect the cutting rate in predetermined trim conditions.

According to the foregoing invention, the cutting rate of the polishing pad can be maintained even if a new dresser is replaced.

According to a preferred aspect of the present invention, the cutting rate measuring section is configured to measure the cutting rate by detecting at least one of: a change in a torque current of a motor for driving the grinding table, and a driving device for driving the trimmer The change in the torque current of the motor and the change in the vertical position of the contact surface of the dresser when the dresser contacts the polishing pad.

Another aspect of the present invention provides a finishing device for trimming a polishing pad on a polishing table. The apparatus includes: a trimmer configured to trim a polishing pad by applying pressure to an upper surface of the polishing pad, the trimmer operable to oscillate within a predetermined range including an upper surface of the polishing pad; and a dresser pretreatment device, setting Used to pre-process the trimmer. The dresser pretreatment device is disposed on a portion of the predetermined range outside the upper surface of the polishing pad.

According to the invention as described above, the dresser can be pretreated without affecting the polishing pad being used.

The dresser pretreatment apparatus preferably oriented to the present invention includes a cutting rate measuring device configured to measure the cutting rate of the polishing pad.

According to the present invention described above, the end point of the trimmer pre-processing can be detected.

The dressing device preferably oriented to the present invention further includes a service life determining member configured to determine the service life of the dresser based on the cutting rate measured by the cutting rate measuring device.

According to the invention as described above, the dresser can be replaced during the life of the trimmer. This keeps the best condition of the polishing pad.

The dresser pre-processing apparatus preferably of the present invention comprises: a torque current measuring unit configured to measure a torque current of a motor driving the trimmer; and an end time detector configured to be based on the torque current The torque current measured by the measuring unit detects the end time of the trimmer pre-processing.

The dressing device preferably oriented by the present invention further comprises a cleaning device, which is constructed in a group, and when the pretreatment device of the dresser is pretreating the dresser, the dressing surface of the dresser is cleaned.

According to the present invention as described above, the thick and solid debris adhering to the dresser during trimming can be removed, and the thick slurry and solid debris can be prevented from being deposited on the dresser. Therefore, the dresser can be maintained in a proper state for trimming the polishing pad.

Another aspect of the present invention provides a finishing device for trimming a polishing pad positioned on a polishing table. The apparatus includes: a trimmer disposed to rotate about its own axis, and trimming the polishing pad by applying pressure to the upper surface of the polishing pad with a predetermined force, and the trimmer is attached to the arm of the dresser; trimming a swinging mechanism arranged to cause the dresser to swing in a radial direction of the polishing pad on the upper surface of the polishing pad; a trimmer position measuring device configured to measure a radial position of the trimmer on the upper surface of the polishing pad; a measuring device configured to measure a cutting rate of the polishing pad trimmed by the dresser; the polishing pad profile measuring device is configured to obtain a polishing pad cutting rate measured at a plurality of regions defined on the upper surface of the polishing pad The contour of the polishing pad, while the position of the plurality of regions is measured by the trimmer position measuring device; and the trimmer operating controller is configured to control the operation of the trimmer. The polishing pad profile measured by the polishing pad profile measuring device is fed back to the trimmer operation controller.

According to the invention as described above, the polishing pad profile measured by the polishing pad profile measuring device is fed back to the trimmer operation controller. Therefore, the polishing pad can be trimmed to conform to the actual contour. In other words, the actual contour can be changed to the desired contour. The plurality of regions can be arranged along the radial direction of the polishing pad.

The preferred embodiment of the dresser swing mechanism includes a motor as a drive source for swinging the trimmer arm, and the dresser position measuring device is configured to measure the dresser based on the pulse number supplied to the motor. Radial position. The motor can be a position control motor or a pulse motor such as a stepper motor or a servo motor.

Another aspect of the present invention provides a substrate polishing apparatus comprising: a polishing table for supporting a polishing pad; a top ring configured to rotate the substrate, and pressing the substrate with a predetermined force while rotating the substrate Resisting to the polishing pad; a top ring operation controller configured to control the operation of the top ring; the trimmer being arranged to rotate about its own axis and by applying pressure to the upper surface of the polishing pad with a predetermined force The polishing pad is trimmed, and the trimmer is attached to the trimmer arm; the trimmer swinging mechanism is configured to swing the trimmer on the upper surface of the polishing pad toward the radial direction of the polishing pad; the trimmer position measuring device is configured to measure The radial position of the dresser on the upper surface of the polishing pad; the cutting rate measuring device is configured to measure the cutting rate of the polishing pad trimmed by the dresser; the polishing pad profile measuring device is set to be defined from the polishing pad The polishing pad cutting rate measured at a plurality of regions in the upper surface to obtain the contour of the polishing pad, and the positions of the plurality of regions are measured by the measuring device of the position of the dresser; the dresser As a controller arranged to control operation of the finisher; contour measuring apparatus and a substrate, arranged to measure the removal of the thin film on the substrate contour (removal profile). The polishing pad profile measured by the polishing pad profile measuring device is fed back to the trimmer operation controller, and the removal profile of the film on the substrate measured by the substrate profile measuring device is fed back to the top ring operation controller. .

According to the invention as described above, the grinding of the substrate and the finishing of the polishing pad can be performed to make the actual contours uniform according to the contour of the polishing pad. In other words, the actual contour can be changed to the desired contour. Therefore, the accuracy of substrate polishing and polishing pad dressing can be improved. Moreover, in accordance with the present invention, the substrate can be abraded using a polishing pad that has been tailored to the desired contour of the polishing pad to have a desired removal profile of the film on the substrate.

Preferably, the trimmer swinging mechanism of the present invention comprises a motor comprising a position control motor or a pulse motor as a drive source for swinging the trimmer arm, and the dresser position measuring device is arranged to be based on the input motor The number of pulses is used to measure the radial position of the dresser.

Another aspect of the present invention is directed to a polishing apparatus for a substrate, comprising: a polishing table for supporting a polishing pad; a top ring configured to rotate the substrate, and pressing the substrate with a predetermined force while rotating the substrate The top is resistant to the polishing pad, and the top ring has a substrate holding surface divided into a plurality of regions; the top ring operation controller is arranged to control the operation of the top ring; the trimmer is set to surround itself The axis rotates, and the polishing pad is trimmed by applying pressure to the upper surface of the polishing pad with a predetermined force, and the trimmer is attached to the arm of the dresser; the dresser swing mechanism is disposed such that the dresser is on the polishing pad a radial swing toward the polishing pad on the upper surface; a trimmer position measuring device configured to measure a radial position of the dresser on the upper surface of the polishing pad; a cutting rate measuring device configured to measure the trimmed by the dresser The cutting rate of the polishing pad; the measuring device of the polishing pad profile is arranged to obtain the contour of the polishing pad from the polishing pad cutting rate measured at a plurality of regions defined in the upper surface of the polishing pad, and The position of the area is measured by the trimmer position measuring device; the trimmer operation controller is arranged to control the operation of the dresser; and the pressure amount controller is configured according to the contour of the polishing pad. The thickness of the polishing pad obtained by the device is measured by the profile of the polishing pad to control the amount of pressure applied to the regions of the substrate holding surface.

According to the invention as described above, the substrate can be suitably ground in accordance with the contour of the polishing pad. For example, feedback control can be implemented such that the amount of applied pressure of the substrate holding surface of the top ring corresponding to the thinner portion of the polishing pad can be selectively adjusted to be higher than the applied pressure of the other regions.

Another aspect of the present invention provides a substrate polishing method comprising: trimming a polishing pad on a polishing table by pressing a rotating trimmer against a top surface of the polishing pad with a predetermined force; During trimming, the trimmer is swung in the radial direction of the polishing pad on the upper surface of the polishing pad; the radial position of the trimmer on the upper surface of the polishing pad is measured; and the measurement is defined at a plurality of regions in the upper surface of the polishing pad. The cutting rate of the pad; the contour of the polishing pad is determined from the cutting rate of the polishing pad; the substrate is held by a top ring having a substrate holding surface divided into a plurality of regions; and the substrate is pressed while rotating the substrate The top surface is resistant to the upper surface of the polishing pad; and the substrate is pressed against the upper surface of the polishing pad, and the pressure of the polishing pad is controlled according to the thickness of the polishing pad according to the contour of the polishing pad to control the pressure in the substrate holding surface power.

According to the invention as described above, the substrate can be suitably ground in accordance with the contour of the polishing pad. For example, the feedback control can be implemented such that the force of the pressing of the substrate holding surface of the top ring corresponding to the thin portion of the polishing pad can be selectively adjusted to be higher than the applied pressure of the other regions.

The polishing pad removal rate of each region to which the present invention is preferably oriented is the measurement of the cutting rate at the central portion of each region of the polishing pad.

The polishing pad removal rate of each region to which the present invention is preferably oriented is the average of the cutting rate measurements at various portions in each region.

Embodiments of the present invention will now be described with reference to the drawings. 2 and 3 are grinding apparatuses having a dressing device according to an embodiment of the present invention. As shown in FIGS. 2 and 3, the polishing apparatus according to this embodiment includes a polishing table 1 which supports the polishing pad 4 on its upper surface, and a top ring (not shown) which is held on the lower surface thereof. A substrate such as a semiconductor wafer, and the substrate is pressed against the upper surface of the polishing pad 4; and the trimmer 3 is configured to trim the upper surface of the polishing pad 4. The polishing table 1 is connected to the motor 7, and will rotate about its own axis as indicated by the arrow A in Fig. 2.

The trimmer 3 is connected to the motor 14 via a power transmission mechanism 15 such as a gear assembly. The trimmer 3 is further connected to an elevating cylinder 16. The dresser 3 can be vertically moved by the lift cylinder 16 in the direction indicated by the arrow B. During the dressing, the lift cylinder 16 moves the dresser 3 downward, and presses the dresser 3 against the polishing pad 4 at a certain pressure, while the motor 14 also causes the dresser 3 to indicate the arrow C. The direction rotates around its own axis. The trimmer 3 is attached to the dresser shaft 8 and has a metal layer 9 as the lower surface of the dresser 3. The diamond particles (not shown) are closely adhered to the metal layer 9 by means of metal plating or the like. Above the polishing table 1, a conditioning liquid supply nozzle 5 is provided for supplying a conditioning liquid (usually pure water) to the polishing pad 4 attached to the upper surface of the polishing table 1. The motor 14 and lift cylinder 16 are controlled by a trimmer operation controller (not shown) to operate the trimmer 3 under the desired trim conditions including the trimmer 3 applied to the polishing pad 4. Pressure, and the speed of the dresser 3.

The dresser 3 has a dresser arm 2 which is oscillated (swinged) by a swing mechanism 6 about a central axis 0 of a swing axis (not shown) in a direction indicated by an arrow D. The swing mechanism 6 includes a gear 6-1, a gear 6-2, and a motor 29 as a drive source. The motor 29 can use a position control motor or a pulse motor. More specifically, the motor 29 can use a servo motor or a stepping motor. When the polishing table 1 and the dresser 3 are rotated about their respective axes, the dresser 3 is lowered, and the diamond particles held on the metal layer 9 are pressed against the upper surface of the polishing pad 4, and the polishing pad 4 is utilized. The relative movement with the dresser 3 scrapes the upper surface of the polishing pad 4, thereby trimming and restoring the upper surface of the polishing pad 4. The dressing device further includes a dresser position measuring device (not shown) which is configured to detect the radial direction of the dresser 3 on the upper surface of the polishing pad 4 in accordance with the number of pulses supplied to the motor 29.

In this example, the dresser arm 2 is oscillated (swinged) in the radial direction of the polishing pad 4 indicated by the arrow D using the swing mechanism 6. However, in addition to the swinging mechanism 6, any type of moving mechanism can be employed as long as the dresser 3 can be moved in the radial direction of the polishing pad 4.

An eddy current sensor 10 is provided in the polishing table 1. The eddy current sensor 10 is configured to induce an eddy current in the metal layer 9 of the trimmer 3 by passing a high frequency current to the sensor coil, and according to the eddy current induced in the metal layer 9. The thickness of the polishing pad 4 is measured by measurement. The polishing pad 4 is made of a dielectric material such as foamed polyurethane. Therefore, if the polishing pad 4 is thick, the eddy current induced in the metal layer 9 of the trimmer 3 is small; if the polishing pad 4 is thin, the eddy current induced in the metal layer 9 is large. Therefore, the thickness of the polishing pad 4 can be determined by measuring the eddy current induced in the metal layer 9. The eddy current sensor 10 has an output connected to the wire 18, and the wire 18 extends through the polishing table 1, the polishing table support shaft 1a, and the rotary connector 11 mounted at one end of the polishing table support shaft 1a to control 12 The controller 12 is connected to the display unit 13. The eddy current sensor 10, the controller 12, and the display unit 13 constitute an eddy current type pad thickness detecting monitor 17. Instead of the rotary connector 11, a slip ring can be used.

In this example, a single eddy current sensor 10 is disposed below the polishing pad 4, as shown in FIG. Another method is to provide a plurality of eddy current sensors under the polishing pad 4. In this case, as shown in FIG. 9, the upper surface of the polishing pad 4 may be divided into a plurality of regions arranged along the radial direction of the polishing pad 4, and an eddy current sensor is disposed below the central portion of the individual region, In order to measure the thickness of the central portion of the individual regions.

By using the eddy current pad thickness detecting monitor 17, the eddy current sensor 10 can detect the thickness variation of the polishing pad 4 according to the eddy current generated in the metal layer 9 of the trimmer 3; The value of the eddy current detected by the eddy current sensor 10 is displayed on the display unit 13, and the thickness of the polishing pad 4 is measured. Based on the signal from the eddy current sensor 10, the controller 12 can measure the cutting rate of the dresser 3 cutting or trimming the polishing pad 4. The measured cutting rate is fed back from the controller 12 to the trimmer operating controller of the control motor 14 and the lift cylinder 16, so that the cutting rate can be reflected in the trimming conditions, such as the trimmer 3 by the lift cylinder 16 The pressure applied to the polishing pad 4, the moving speed of the dresser 3 in the radial direction on the upper surface of the polishing pad 4, and the rotational speed of the motor 14 rotating the dresser 3.

In the present embodiment, the cutting rate of the polishing pad 4 trimmed by the trimmer 3 is measured by the eddy current sensor 10. Alternatively, the cutting rate can be measured by detecting a change in the torque current of the motor 7 that drives (rotates) the polishing table 1 or detecting the rotation of the motor 14 that drives the (rotating) dresser 3. The change in the moment current; or the change in the vertical position of the contact surface of the dresser 3 contacting the polishing pad 4; or a combination of these variations. The change in the vertical position of the contact surface of the dresser 3 can be detected by measuring the change in the vertical position of the trimmer 3. As described above, the radial position of the dresser 3 on the upper surface of the polishing pad 4 is detected by the number of pulses supplied to the motor 29 (e.g., position control motor or pulse motor). However, any means or means can be employed as long as it is capable of detecting the radial position of the dresser 3 on the upper surface of the polishing pad 4.

In the above-mentioned grinding device, due to the different properties of the individual dressers, replacing the dresser 3 with a new dresser may cause a change in the degree of cutting (ie, cutting rate) of the polishing pad 4, resulting in a removal rate and a film on the substrate. The change in the grinding profile. After the dresser 3 is replaced with a new dresser, the new dresser is typically pre-treated by applying a new dresser to the polishing pad 4 at a specified pressure. However, the pretreatment process is tricky because it may have an adverse effect on the abrasive performance, particularly at the beginning of the polishing of the substrate W. Therefore, in the present embodiment, the polishing apparatus has a dresser pretreatment apparatus 20, which is configured to perform pretreatment on the new finisher 3 after replacing the old finisher with the new finisher 3, as shown in Fig. 3. Shown. The pretreatment device 20 of the dresser is disposed at the idle position of the dresser 3, that is, at the end of the swinging range of the dresser 3 outside the upper surface of the polishing pad 4.

Fig. 4A is a side view showing the dresser pretreatment device 20, and Fig. 4B is a plan view showing the dresser pretreatment device 20. As shown in FIGS. 4A and 4B, the dresser pretreatment apparatus 20 has a dresser pretreatment section 23 including a base 21 and a dresser pretreatment member 22 attached to the base 21. The dresser pre-processing section 23 is supported by the support shaft 27. The dresser pre-processing section 23 can be vertically moved in the direction indicated by the arrow E by a vertical moving mechanism (not shown); and can be wound in the direction indicated by the arrow F by a motor (not shown) Rotate your own axis. The dresser pretreatment member 22 is made of the same material as the polishing pad 4, such as a foamed polyurethane. The dresser pretreatment member 22 has a plurality of cleaning liquid injection holes 24 that open upward for discharging the cleaning liquid, and the cleaning liquid is supplied through a cleaning liquid supply pipe (not shown) provided in the base 21. A radially-oriented dresser cleaning brush 25 (such as a nylon brush) can be attached to the position of the dresser pre-treating portion 23 that passes the dresser cleaning brush 25 through the center of the dresser pre-treatment member 22.

Generally, as shown in Fig. 5, the dresser pretreatment portion 23 is immersed in the cleaning liquid Q of the cleaning liquid tank 26 so as to be kept moist. A sealing mechanism 28 is provided around the support shaft 27 to prevent the cleaning liquid Q from leaking out of the outer portion of the cleaning liquid tank 26. After replacing the used dresser with the new dresser 3, the pre-treatment portion 23 of the dresser will rise toward the new dresser 3 that has been positioned in the idle position directly above the dresser pre-treatment portion 23, and is scheduled The force exerts pressure on the lower surface of the dresser 3 as shown in Fig. 6. In this state, the dresser pre-processing section 23 rotates around its own axis in the direction indicated by the arrow F, while the dresser 3 also rotates around its own axis in the direction indicated by the arrow C, resulting in The relative movement between the dresser pre-treatment portion 23 and the dresser 3. Due to this relative movement, the dresser 3 is pretreated while the upper surface of the dresser pretreatment member 22 is also scraped off by the dresser 3. The pressure applied by the dresser pre-processing section 23 and the rotational speed of the dresser pre-processing section 23 are controlled by a controller (not shown). The pre-processing portion 23 of the dresser may also be held stationary instead of rotating the dresser 3 and the dresser pre-processing portion 23 at the same time.

The dresser pretreatment apparatus 20 has an eddy current sensor (not shown) provided in the susceptor 21 of the dresser pretreatment section 23. The eddy current sensor is identical to the eddy current sensor 10 of FIG. 2 and is used to measure the thickness variation of the dresser pretreatment member 22 and to measure the cutting rate of the dresser pretreatment member 22. . The measured cutting rate is compared with the cutting rate previously measured by the dresser 3 under normal conditions. If the measured cutting rate is normal, it can be judged that the pre-processing program has reached the pre-processing end point and the pre-processing procedure is ended. If the measured cutting rate is not normal, the dresser pre-processing section 23 continues to pre-treat the dresser 3 to adjust the cutting rate.

In general, the cutting rate of the dresser 3 against the polishing pad 4 will gradually decrease as the edge of the diamond grain is worn during the life of the dresser 3. However, the new dresser tends to exhibit a rapid drop in the cutting rate of the polishing pad 4 at the beginning of its service life, and the reduction in the cutting rate will not be so severe until a certain period of time. Therefore, it is possible to judge the end of the pre-processing of the trimmer 3 by detecting the time point at which the drop in the cutting rate is not so severe.

The cutting rate of the dresser pretreatment member 22 may be by a torque current for driving the motor 14 of the dresser 3 (see Fig. 2) or a motor for driving the trimmer pretreatment portion 23 (not shown) The torque current, or a combination of the two torque current values, is measured. Alternatively, a trimmer vertical position sensor (not shown) may be provided for measuring the vertical position of the dresser 3 during trimming so that the trim rate of the dresser pretreatment member 22 may be based on the dresser The output signal of the vertical position sensor is measured.

After the pre-processing of the dresser 3 is completed, at least one of the dresser 3 and the dresser pre-treating portion 23 is moved away from each other so as to be on the lower surface of the dresser 3 and the dresser pre-processing member 22. A gap is formed between the surfaces as shown in Fig. 7. Thereafter, the dresser cleaning brush 25 is brought into contact with the lower surface of the metal layer 9 which firmly holds the diamond particles. In this state, the cleaning liquid q (for example, pure water, a chemical solution or a mixture of pure water, a chemical solution, and nitrogen) is ejected from the cleaning liquid injection hole 24 of the dresser pretreatment member 22 to the metal layer 9, whereby The lower surface of the metal layer 9 is cleaned. In this way, deposits such as thick paste can be removed from the lower surface of the metal layer 9.

After the pre-treatment and cleaning procedures are completed, and when the polishing apparatus is grinding the substrate, the lower surface of the metal layer 9 is immersed in the cleaning liquid Q in the cleaning liquid tank 26, as shown in FIG. In this idle position, the dresser 3 is rotated about its own axis while the lower surface of the metal layer 9 is brought into contact with the dresser cleaning brush 25 to keep the lower surface of the metal layer 9 wet and clean. The lower surface of the dresser 3 thus remains wet and clean.

The dresser 3 of the polishing pad 4 has been used for a long time, and the cutting rate thereof is lowered. When the cutting rate is lowered to a predetermined level, it is judged that the dresser 3 has a long service life, and the trimmer 3 is replaced with a new dresser. The dresser pre-treatment device 20 can be used to determine if the dresser 3 has reached the end of its useful life. In more detail, the dresser pretreatment apparatus 20 may have a dresser life determining portion that judges the end point of the service life of the dresser 3 based on the cutting rate of the dresser pretreatment member 22. To determine the end of the service life of the dresser 3 that has been used to trim the polishing pad 4, the dresser 3 is placed on the dresser pretreatment device 20 and the dresser pretreatment member 22 is trimmed. The dresser life determining portion measures the cutting rate of the dresser pre-processing member 22, and judges whether the dresser 3 has reached the service life based on the measured cutting rate.

During the pre-treatment of the newly replaced dresser 3 by the dresser pre-treatment device 20, the torque current of the motor 14 used to drive the dresser 3 will change as the pre-treatment progresses. For example, the torque current of the motor 14 will gradually decrease during the pre-processing process until the pre-processing process is near completion. Therefore, it is possible to detect the pre-processing end point of the dresser 3 by monitoring the torque current of the motor 14.

The finisher 3 trims the upper surface of the polishing pad 4 on the polishing table 1 after each time the polishing of one substrate is completed. At the time of dressing, the rotating dresser 3 presses the upper surface of the polishing pad 4 on the rotating polishing table 1 with a predetermined pressure. In more detail, as shown in FIG. 3, when the dresser 3 presses the trimming surface against the upper surface of the polishing pad 4, the dresser 3 is along the radial direction of the polishing pad 4 indicated by the arrow D. Repeatedly swing or swing around the central axis 0. A dressing procedure of the polishing pad 4 is carried out by a plurality of oscillating motions (i.e., repeated oscillating motions) of the dresser 3 in the rotation on the polishing pad 4. The measurement of the contour (the shape of the upper surface) of the trimmed polishing pad 4 is performed by measuring the thickness of the predetermined points a to e (i.e., the height of the upper surface) of the polishing pad 4 in a plurality of regions, and the The regions are arranged along the radial direction on the upper surface of the polishing pad 4 as shown in Fig. 9.

If the thickness of the polishing pad 4 at five points a to e is to be sequentially measured in a single oscillating motion of the dresser 3, high-speed data processing is required. Therefore, there is a need for an expensive data processor capable of implementing such high speed data processing. Therefore, in the present embodiment, only the thickness of the polishing pad 4 of one of a to e is measured in each trimming process. In other words, when each dresser 3 performs a trimming process, only the thickness of the polishing pad 4 of one of the plurality of regions is measured. For example, measuring the thickness of the polishing pad 4 at point a during the first trimming process, measuring point b during the second trimming process, measuring point c during the third trimming process, and during the fourth trimming process Measure d point and measure point e during the fifth trimming process. In this manner, after a plurality of dressing processes (in this example, five dressing processes for points a to e), the thickness of the polishing pad 4 of the polishing pad 4 at each of points a to e is measured. In order to prevent the adverse effects of noise on the measurement, the thickness of the polishing pad 4 at each point a to e is measured a plurality of times, and the average of the measured values of the points a to e is calculated. This calculated average value is used as the thickness of the polishing pad 4 at each point. For example, in Figure 9, the thickness of the polishing pad 4 at point a is measured multiple times, and the average of multiple measurements is taken as the thickness at point a. The thickness of the polishing pad 4 at point b is measured multiple times, and the average of multiple measurements is taken as the thickness at point b. The thickness of the polishing pad 4 at points c to e is also measured in the same manner.

As described above, the thickness of the polishing pad 4 is repeatedly measured until a measurement value of the thicknesses of all the predetermined points in the plurality of regions is obtained. Therefore, after grinding a plurality of substrates and trimming the polishing pad 4 a plurality of times, the contour of the polishing pad 4 can be measured (or determined) from the measured values. Repeat this set of measurement steps several times to calculate the average profile from the thickness measurements. The resulting average profile is taken as the contour of the polishing pad 4 and is reflected in the grinding recipe. In the example of Fig. 9, after the five substrates were ground and the polishing pad 4 was trimmed five times, the thickness of the polishing pad 4 at points a to e was measured, thereby obtaining a profile of the polishing pad 4. This set of steps was repeated three times (i.e., the substrate was ground fifteen times) to use the average profile calculated from the measurement results as the outline of the polishing pad 4 and reflected in the abrasive formulation.

Fig. 10 is a schematic view of a substrate polishing apparatus according to an embodiment of the present invention. The finishing process of the polishing pad 4 is carried out as follows. The polishing table 1 is rotated in the direction indicated by the arrow A, and the dresser 3 is rotated in the direction indicated by the arrow C. The dresser 3 applies pressure to the upper surface of the polishing pad 4 attached to the upper surface of the polishing table 1 with a predetermined force. In this state, the dresser 3 reciprocates the radial direction of the polishing pad 4 indicated by the arrow D by the rocking movement of the dresser arm 2 (see FIG. 3), thereby trimming the polishing pad 4 . The upper surface of the polishing pad 4 is divided into annular regions Z1 to Z7 disposed along the radial direction of the polishing pad 4. During the trimming process, the position of the dresser 3 on the central portion of the zones Z1 to Z7 is detected by the number of pulses supplied to the motor 29 (which is a position control motor or a pulse motor), thereby measuring The thickness of the polishing pad 4 in the central portion of the regions Z1 to Z7 is obtained. The radial position of the dresser 3 on the upper surface of the polishing pad 4 can be accurately detected by the number of pulses supplied to the motor 29. Symbols T1 to T7 in Fig. 10 indicate the measured values of the thicknesses of the polishing pads 4 in the central portions of the respective regions Z1 to Z7, respectively.

The trim profile of the polishing pad 4 is measured from the measured values T1 to T7 of the thickness of the polishing pad 4 in the regions Z1 to Z7. The contour is fed back to the trimmer operation controller and is reflected in the trim conditions (eg, the pressure applied by the dresser 3 to the polishing pad 4, the radial movement speed of the dresser 3 on the upper surface of the polishing pad 4, and the rotational speed of the dresser 3) )in. This results in an ideal trim profile of the polishing pad 4.

The symbol 30 denotes a top ring which is configured to hold the substrate W with its lower surface and rotate the substrate W around a rotation axis (not shown) in a direction indicated by an arrow G. This top ring 30 has a retainer ring 32 on its lower periphery. Pressure chambers M1 to M4 are provided in the buckle 32. These pressure chambers M1 to M4 are formed by a membrane 41. The lower surface of this film 41 is a support surface for supporting the substrate W. By adjusting the pressure in the pressure chambers M1 to M4, the pressure applied to the polishing pad 4 through the substrate W contacting the pressure chamber can be controlled.

The pressure controllers are respectively disposed in fluid conduits in fluid communication with the respective pressure chambers M1 to M4. These pressure controllers are controlled in accordance with the measured values T1 to T7 representing the thickness of the polishing pad 4 in the regions Z1 to Z7 to adjust the pressure in the pressure chambers M1 to M4 formed by the film 41. By these operations, the pressure chambers M1 to M4 can provide a pressure distribution according to the thickness of the polishing pad 4. This allows an appropriate grinding profile (or profile removal) of the film on the substrate W to be achieved without being affected by the trim profile of the polishing pad 4. In one example, the pressure in the pressure chamber corresponding to the region (site) having the smaller thickness measurement of the polishing pad 4 is selectively adjusted to be higher than the other pressure corresponding to the region (site) having a larger measurement value. The pressure of the cavity allows the polishing rate (removal rate) of the film on the substrate W to be averaged over the entire surface thereof. However, the invention is not limited to this type of pressure adjustment. Basically, the feedback control is implemented such that the pressing force of each zone is adjusted in accordance with the contour of the polishing pad 4 to obtain the desired grinding profile. When the substrate is continuously ground, the profile of the polishing pad changes over time, so changes in the profile of the polishing pad can also be incorporated into the variables of the pressure control.

The pressure chamber corresponding to the region (site) having the smaller thickness measurement of the polishing pad 4 is selectively adjusted to be higher than the pressure corresponding to the other pressure chambers of the region (site) having the larger measurement value. Furthermore, the trim profile of the polishing pad 4 is fed back to the trimmer operating controller to achieve the desired trim profile of the polishing pad 4. The pressure in the pressure chambers M1 to M4 is adjusted in accordance with the resulting trim profile of the polishing pad 4. Therefore, a more appropriate polishing profile of the film on the substrate W can be achieved.

Figure 11 is a vertical sectional view showing a schematic structure of a top ring used in a substrate polishing apparatus according to an embodiment of the present invention. The top ring 30 has a top ring body 31 which is in the shape of a cylindrical container, and a buckle 32 which is fixed to a lower end portion of the top ring body 31. An annular pressure piece 33 is provided in the top ring body 31. The pressure piece 33 is interposed between the top ring body 31 and the pressure piece supporting member 34, and is supported by the lower surface around the inside of the top ring body 31. The top ring drive shaft 35 is disposed at the center of the upper surface of the top ring body 31. The top ring body 31 and the top ring drive shaft 35 are coupled together through a universal joint 36. The universal joint 36 includes: a spherical bearing mechanism having bearing balls 37 for tilting the top ring body 31 and the top ring drive shaft 35 relative to each other; and a rotary transmission mechanism not shown, the top ring drive shaft 35 The rotation is transmitted to the top ring body 31. The top ring body 31 is tiltable relative to the top ring drive shaft 35 and receives rotation of the top ring drive shaft 35 for rotation.

In the inner space defined by the top ring body 31 and the buckle 32, there is a dish-shaped chucking plate 38. The chuck 38 is held on the lower surface of the pressure piece 33 by the chuck holding member 39. The top ring body 31, the pressure piece 33 and the chuck 38 define a pressure chamber M5 on the chuck 38. The pressure piece 33 is composed of an elastic material such as rubber. As the pressure within the pressure chamber M5 rises or falls, the chuck 38 also drops or rises. The lower surface of the chuck 38 serves as a holding surface for holding the substrate W.

The annular films 41a, 41b, 41c, and 41d are disposed on the lower surface of the chuck 38. The upper edge of the film 41a is inserted between the chuck 38 and the annular film holder 51 such that the film 41a is mounted on the central portion of the lower surface of the chuck 38. The upper edge of the film 41b is inserted between the chuck 38 and the annular film holder 51 such that the film 41b is mounted on the lower surface of the chuck 38. This film 41b is disposed around the film 41a. The upper edges of the films 41c and 41d are inserted between the chuck 38 and the annular film holder 52 such that the films 41c and 41d are mounted on the peripheral portion of the lower surface of the chuck 38. The film 41c is disposed around the film 41b, and the film 41d is disposed around the film 41c. The pressure chambers M1, M2, M3, and M4 are formed by the films 41a, 41b, 41c, and 41d, the substrate W, and the chuck 38.

Fluid conduits 42, 43, 44, 45 are connected to pressure chambers M1, M2, M3, M4, respectively. These fluid conduits 42, 43, 44, 45 are in fluid communication with a source of compressed air 48 via pressure controllers P1, P2, P3, P4. The fluid conduit 46 is connected to the pressure chamber M5 and this fluid conduit 46 is also connected to the compressed air source 48 via a pressure controller P5. Symbols S1, S2, S3, S4 in Fig. 11 represent sensors, each of which is used to measure the velocity and pressure of a fluid (compressed air) flowing through each of the fluid conduits 42, 43, 44, 45. With traffic.

In the above top ring 30, the pressure controller P5 is operated to control the air pressure to be supplied from the compressed air source 48 to the pressure chamber M5 via the fluid conduit 46 to control the upper surface of the top anti-polishing pad 4 on the entire surface of the substrate W. Apply pressure. In addition, the pressure controllers P1, P2, P3, P4 are operated to control the air pressure to be supplied from the compressed air source 48 through the fluid conduits 42, 43, 44, 45 to the pressure chambers M1, M2, M3, M4 so that the control is located The pressure applied to the region (portion) of the substrate W under the pressure chambers M1, M2, M3, M4.

The velocity, pressure and flow rate of the fluid (compressed air) flowing through the fluid conduits 42, 43, 44, 45 are measured by the sensors S1, S2, S3, S4, and these measured values D1 are sent to the controller 50. . Several types of data D2 (including the abrasive profile required to polish the substrate W and the measured polishing pad profile) are stored in the controller 50. The controller 50 is configured to calculate the pressure to be established in the pressure chambers M1, M2, M3, M4 during the polishing of the substrate W from the data D2 and the measurement data D1 to achieve the target polishing profile. Furthermore, the controller 50 is also configured to calculate the speed, pressure and flow rate of the compressed air to be supplied to the pressure chamber, and to send control signals CS1, CS2, CS3 to the pressure controllers P1, P2, P3, P4, P5. , CS4, CS5, in order to control the speed, pressure and flow rate of the compressed air to be supplied to the pressure chambers M1, M2, M3, M4, M5 by the controllers P1, P2, P3, P4, P5.

Figure 12 is a flow chart showing the polishing profile of the polishing pad as measured above during the polishing of the substrate. The grinding profile required for the film on the substrate is input to the controller 50 (step ST1). Thereafter, the polishing of the polishing pad 4 is performed (step ST2). The thickness of the polishing pad 4 is measured at each region to obtain (i.e., measure) the thickness profile of the polishing pad 4 (step ST3). On the other hand, the polishing of the substrate W is carried out (step ST4), and the polishing rate of the film on the substrate W is measured to obtain the polishing profile data (step ST5).

The thickness profile of the polishing pad 4 obtained in step ST3 is compared with the ideal thickness profile of the polishing pad 4, and the polishing profile obtained in step ST5 is compared with the ideal polishing profile (step ST6). Next, it is judged from the comparison result of step ST6 whether or not the difference between the obtained contour and the ideal contour is within the range of the predetermined value. When the difference is within the predetermined value (ie "YES"), the process ends. On the other hand, when the difference exceeds the predetermined value (i.e., "NO"), calculation for changing the trimming condition and the grinding condition is performed (step ST8).

The trimming conditions are changed according to the above calculation results (for example, the application pressure of the trimmer 3 applied to the respective regions Z1 to Z7 of the upper surface of the polishing pad 4, the rotational speed of the dresser 3, and the moving speed of the dresser 3 in the direction indicated by the arrow D (Step ST9), and polishing of the substrate is performed. In this way, changes in the conditioning conditions are fed back to the trimmer operating controller. Further, the conditions of the polishing (for example, the pressures in the pressure chambers M1 to M4) are changed in accordance with the above calculation results (step ST10), and the polishing of the substrate is performed. In this manner, changes in the grinding conditions are fed back to the top ring operating controller used to control the operation of the top ring 30.

Although only a particular preferred embodiment of the invention has been shown, it is understood that various changes and modifications may be made without departing from the scope of the appended claims.

1. . . Grinding table

1a. . . Support shaft

2. . . Dresser arm

3. . . Dresser

4. . . Abrasive pad

5. . . Liquid supply nozzle

6. . . Swing mechanism

6-1, 6-2. . . gear

7. . . motor

8. . . Dresser axis

9. . . Metal layer

10. . . Eddy current sensor

11. . . Rotary connector

12. . . Controller

13. . . Display unit

14. . . motor

15. . . Power transmission mechanism

16. . . Lifting cylinder

17. . . Abrasive pad thickness detection monitor

18. . . wire

20. . . Dresser pretreatment device

twenty one. . . Pedestal

twenty two. . . Dresser pretreatment component

twenty three. . . Dresser pre-processing department

twenty four. . . Cleaning fluid injection hole

25. . . Dresser cleaning brush

26. . . Cleaning tank

27. . . Support shaft

28. . . Sealing mechanism

29. . . motor

30. . . Top ring

31. . . Top ring body

32. . . Buckle

33. . . Pressure film

34. . . Pressure piece support member

35. . . Top ring drive shaft

36. . . Universal joint

37. . . Bearing ball

38. . . Chuck

39. . . Chuck holding member

41. . . film

41a, 41b, 41c, 41d. . . Ring film

42, 43, 44, 45, 46. . . Fluid pipeline

48. . . Compressed air source

50. . . Controller

52. . . Ring film holder

100. . . Abrasive pad

102. . . Grinding

104. . . Top ring

106. . . nozzle

108. . . Dresser

A, B, C, D, E, F, G. . . arrow

a, b, c, d, e. . . Reservation point

CS1, CS2, CS3, CS4, CS5. . . Control signal

D1, D2. . . Measurements

M1, M2, M3, M4, M5. . . Pressure chamber

P1, P2, P3, P4, P5. . . pressure controller

Q. . . Cleaning fluid

S1, S2, S3, S4. . . Sensor

T1, T2, T3, T4, T5, T6, T7. . . Thickness measurement

W. . . Substrate

Z1, Z2, Z3, Z4, Z5, Z6, Z7. . . Annular zone

Figure 1 is an example showing a grinding device having a conventional dressing device;

2 is a schematic cross-sectional view showing an example of a polishing apparatus having a finishing device according to an embodiment of the present invention;

Figure 3 is a schematic plan view of a polishing apparatus having a finishing device in accordance with an embodiment of the present invention;

4A is a schematic side view showing an example of a dresser pretreatment apparatus for a dressing apparatus according to an embodiment of the present invention;

Figure 4B is a schematic plan view of the dresser pretreatment device;

Figure 5 is a cross-sectional view showing a dresser pretreatment apparatus in a general state according to an embodiment of the present invention;

Figure 6 is a cross-sectional view showing the dresser pretreatment apparatus when the dresser is pretreated according to an embodiment of the present invention;

Figure 7 is a cross-sectional view showing the dresser pretreatment apparatus when the trimmer is cleaned according to an embodiment of the present invention;

Figure 8 is a cross-sectional view showing a dresser pre-processing apparatus in a waiting state according to an embodiment of the present invention;

The top view of Fig. 9 is a view showing the process of measuring the profile of the polishing pad by the dressing device according to an embodiment of the present invention;

Figure 10 is a schematic view of a substrate polishing apparatus according to an embodiment of the present invention;

11 is a vertical sectional view showing a schematic structure of a top ring for a substrate polishing apparatus according to an embodiment of the present invention;

Figure 12 is a flow chart showing the trimming profile of the polishing pad during the substrate polishing process.

1. . . Grinding table

3. . . Dresser

4. . . Abrasive pad

30. . . Top ring

32. . . Buckle

41. . . film

A, C, D, G. . . arrow

M1, M2, M3, M4. . . Pressure chamber

T1, T2, T3, T4, T5, T6, T7. . . Thickness measurement

W. . . Substrate

Z1, Z2, Z3, Z4, Z5, Z6, Z7. . . Annular zone

Claims (2)

A method for measuring the profile of a polishing pad, wherein the dresser abuts the polishing pad on the polishing table to trim the polishing pad under predetermined finishing conditions, and measures the contour of the polished polishing pad, the method is as follows: The dresser oscillates on the upper surface of the polishing pad in the radial direction of the polishing pad, and performs trimming of the program by trimming by a plurality of oscillating motions; dividing the aforementioned polishing pad into a radial direction a plurality of regions, wherein the height of the upper surface of the polishing pad at a predetermined point of one of the plurality of regions is measured by trimming performed by the one-time swinging motion of the trimmer, and by the next time of the trimmer The trimming performed by the oscillating motion measures the height of the upper surface of the polishing pad at a predetermined point in different regions, and in this way, the trimming by the oscillating motion of the trimmer is sequentially measured to measure the predetermined time in the different region. The height of the upper surface of the polishing pad at the point, and the measurement in all areas is measured by the trimming performed by the plurality of trimming movements of the trimming process described above. The polishing pad at the height of the surface point, and the profile obtained from a measurement result of the polishing pad. The method for measuring a profile according to claim 1, wherein the height of the upper surface of the polishing pad at a predetermined point in the foregoing region is measured by a plurality of processes, and the average value is used. The height of the upper surface of the polishing pad at the predetermined point is obtained to obtain the contour of the aforementioned polishing pad.