JP2007181910A - Polishing apparatus and polishing method - Google Patents

Abstract

There is provided a polishing apparatus capable of obtaining a uniform polishing profile while maintaining a high polishing rate of a surface to be polished even in a CMP process in which the polishing rate of the surface to be polished is highly dependent on the polishing surface temperature.
In a polishing apparatus in which a surface to be polished 9 is brought into contact with a polishing surface 8 of a polishing table 1 and the surface to be polished 9 is polished by relative movement between the surface to be polished 9 and the polishing surface 8, the polishing surface 8 is provided. A polishing surface temperature control means 20 comprising a fluid blowing mechanism 30 for blowing a gas such as a compressed gas toward the surface, a thermography 40 for measuring the temperature distribution of the polishing surface 8, and a controller 50 was provided. When polishing the surface 9 to be polished, the polishing surface temperature control means 20 controls the blowing of fluid by determining the gas blowing flow rate, temperature, and spraying position based on the measurement result of the thermography 40, and polishing. By making the surface 8 have a predetermined temperature distribution, the polishing rate of the surface 9 to be polished is made uniform.
[Selection] Figure 1

Description

  The present invention is a polishing method in which a surface to be polished such as a semiconductor substrate held by a substrate holding mechanism is brought into contact with a polishing surface such as a polishing table and the surface to be polished is polished by relative movement of the surface to be polished and the polishing surface. The present invention relates to an apparatus and a polishing method.

  Conventionally, a polishing target substrate (hereinafter referred to as “substrate”) such as a semiconductor substrate is formed by attaching a polishing cloth (polishing pad) to an upper surface of a polishing table to form a polishing surface and holding the polishing surface by a substrate holding mechanism (top ring). The surface to be polished is brought into contact with the surface to be polished and the surface to be polished is made flat and mirror-like by the relative movement of the surface to be polished and the surface to be polished by the rotation of the polishing table and the rotation of the top ring while supplying the slurry to the polishing surface. There is a chemical mechanical polishing (CMP) apparatus for polishing.

Here, uniform polishing of the surface to be polished of the substrate in the above-described CMP apparatus is important for efforts to miniaturize semiconductor devices. Therefore, conventionally, as shown in Patent Document 1, for example, by adjusting the contact pressure of the polishing surface to the surface to be polished to optimize the surface pressure distribution in the surface to be polished, the surface to be polished of the substrate is in a uniform state. Attempts have been made to polish.
JP 2002-86347 A

  However, the polishing rate (polishing rate) of the surface to be polished of the substrate is affected not only by the contact pressure of the polishing surface but also by the temperature of the polishing surface and the concentration of the slurry to be supplied. Therefore, the contact pressure of the polishing surface is adjusted. The polishing rate could not be completely controlled by itself. In particular, in a CMP process in which the polishing rate is highly dependent on the polishing surface temperature (for example, when the surface hardness of the polishing cloth is highly dependent on the temperature), the temperature distribution of the polishing surface causes each part in the surface to be polished to The polishing rate varied and the polishing profile was not uniform. The temperature of the polishing surface is generally determined by the heat generated by the polishing surface itself due to contact with the surface to be polished or with the retainer ring that holds the substrate attached to the top ring, variation in the heat absorption rate of the polishing surface, Depending on the flow of the slurry dripped onto the surface, the temperature is not uniform and a temperature difference is generated in various places.

  In the CMP process in which the polishing rate is highly dependent on the polishing surface temperature as described above, the polishing rate is proportional to the contact pressure while the contact pressure of the polishing surface to the surface to be polished is within a predetermined range. When the pressure exceeds a predetermined range, the polishing rate does not change even if the contact pressure changes. In this case, even if the contact pressure of the part where the temperature is different from that of the other part in the surface to be polished is locally changed, the polishing rate of the part cannot be changed, and the variation in the polishing rate in the surface to be polished is caused. I could not correct it. Thus, it was not possible to obtain a uniform polishing profile over the entire surface to be polished only by adjusting the contact pressure on the polishing surface.

  On the other hand, if the contact pressure of the entire contact portion of the polishing surface with respect to the surface to be polished is lowered, the temperature rise of the polishing surface can be suppressed, and the controllability of the polishing profile due to the change in contact pressure is improved. As a result, the polishing rate is lowered, and the productivity is deteriorated. Thus, conventionally, it has been difficult to obtain a uniform polishing profile while maintaining a high polishing rate.

  The present invention has been made in view of the above points, and its purpose is to maintain a high polishing rate of the surface to be polished even in a CMP process in which the polishing rate of the surface to be polished is highly dependent on the polishing surface temperature. An object of the present invention is to provide a polishing apparatus and a polishing method capable of obtaining a uniform polishing profile.

  In order to solve the above-mentioned problems, an invention according to claim 1 of the present application includes a substrate holding mechanism for holding a substrate and a polishing table having a polishing surface, and the polishing surface of the substrate held by the substrate holding mechanism is a polishing table. In a polishing apparatus that contacts a polishing surface of the polishing table and polishes the surface to be polished by relative movement of the surface to be polished and a polishing surface, polishing surface temperature control means for controlling a temperature distribution of the polishing surface of the polishing table is provided, and the polishing surface The temperature distribution of the polishing surface is controlled to a predetermined temperature distribution by the temperature control means, and the polishing rate of each part of the surface to be polished of the substrate is controlled.

  According to a second aspect of the present invention, in the polishing apparatus according to the first aspect, the polishing surface temperature control means blows a fluid toward the polishing surface of the polishing table so that the polishing surface has a predetermined temperature. It is characterized by having a fluid blowing mechanism for distribution.

  The invention according to claim 3 of the present application is the polishing apparatus according to claim 2, wherein the fluid blowing mechanism includes a plurality of fluid blowing ports.

  According to a fourth aspect of the present invention, in the polishing apparatus according to the third aspect, the flow rate adjusting means for individually adjusting the flow rate of the fluid blown out from the plurality of fluid outlets and / or the plurality of fluid outlets. It is characterized by comprising temperature adjusting means for individually adjusting the temperature of the fluid blown out from the liquid.

  Invention of Claim 5 of this application WHEREIN: The polishing apparatus of Claim 3 or 4 WHEREIN: Outlet adjustment means which adjusts the number of the fluid outlets which blow out the fluid among these fluid outlets, and / or Alternatively, spray position adjusting means for adjusting the spray position of the fluid onto the polishing surface of each fluid outlet is provided.

  The invention according to claim 6 of the present application is the polishing apparatus according to claim 4 or 5, further comprising polishing surface temperature distribution measuring means for measuring the temperature distribution of the polishing surface of the polishing table, and the polishing surface temperature control means. Is based on the measurement result of the polishing surface temperature distribution measuring means by controlling the flow of fluid using at least one of the flow rate adjusting means, the temperature adjusting means, the outlet number adjusting means, or the spray position adjusting means. The polishing surface is controlled to have a predetermined temperature distribution.

  The invention according to claim 7 of the present application has a polishing step of bringing the polishing surface of the substrate into contact with the polishing surface and polishing the polishing surface by relative movement of the polishing surface and the polishing surface, and performing the polishing step. In this case, the polishing method is characterized in that the polishing rate of each part of the surface to be polished of the substrate is controlled by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution.

  The invention according to claim 8 of the present application has a polishing step of bringing the polishing surface of the substrate into contact with the polishing surface and polishing the polishing surface by relative movement of the polishing surface and the polishing surface, A polishing surface temperature control means for controlling the temperature distribution of the polishing surface; a first polishing step for polishing by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution; and a polishing surface by the polishing surface temperature control means And a second polishing step in which polishing is performed without controlling the temperature distribution.

  The invention according to claim 9 of the present application is the polishing method according to claim 8, wherein the first polishing step blows fluid toward the polishing surface by a fluid blowing mechanism provided in the polishing surface temperature control means. The second polishing step is a step of performing polishing by stopping the blowing of fluid by the fluid blowing mechanism.

  The invention according to claim 10 of the present application has a polishing step of bringing the polishing surface of the substrate into contact with the polishing surface and polishing the polishing surface by relative movement of the polishing surface and the polishing surface, A first polishing step for performing polishing by controlling the temperature of the polishing surface to a predetermined temperature distribution by a polishing surface temperature control means for controlling the temperature of the polishing surface; and the polishing surface by the polishing surface temperature control means. And a second polishing step for performing polishing while controlling the temperature distribution to a temperature distribution higher than the temperature distribution in the first polishing step.

  According to an eleventh aspect of the present invention, in the polishing method according to the tenth aspect, the first polishing step is a fluid blowing mechanism provided in the polishing surface temperature control means, and a predetermined flow rate toward the polishing surface. The second polishing step is a step of performing polishing by blowing out a fluid having a flow rate smaller than the flow rate of the fluid in the first step by the fluid blowing mechanism. It is characterized by being.

  The invention according to claim 12 of the present application has a polishing step of bringing the surface to be polished into contact with the polishing surface and polishing the surface to be polished by relative movement of the surface to be polished and the polishing surface, First polishing is performed by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution by blowing unhumidified gas toward the polishing surface by a fluid blowing mechanism that blows fluid toward the polishing surface. And a second polishing step of performing polishing by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution by blowing the gas humidified toward the polishing surface by the fluid ejection mechanism. There is a characteristic polishing method.

  Invention of Claim 13 of this application WHEREIN: In the grinding | polishing method of any one of Claims 8 thru | or 12, the time of the said 1st grinding | polishing process occupies the time more than half of the whole grinding | polishing process. Features.

  According to the first aspect of the present invention, the polishing surface temperature control means for controlling the temperature distribution of the polishing surface of the polishing table is provided, and the temperature distribution of the polishing surface is controlled to a predetermined temperature distribution by the polishing surface temperature control means. In addition, since the polishing rate of each part of the surface to be polished of the substrate is controlled, even in the CMP process in which the polishing rate of the surface to be polished is highly dependent on the polishing surface temperature, without reducing the surface pressure of the entire surface to be polished, Each part of the surface to be polished can be polished at a desired polishing rate, and a uniform polishing profile can be obtained while maintaining a high polishing rate on the surface to be polished.

  According to the invention described in claim 2 of the present application, the polishing surface temperature control means includes a fluid blowing mechanism that blows the fluid toward the polishing surface of the polishing table so that the polishing surface has a predetermined temperature distribution. It becomes possible to make the polishing surface have a desired temperature distribution with a simple configuration, and a uniform polishing profile can be obtained.

  According to the invention described in claim 3 of the present application, since the fluid blowing mechanism includes a plurality of fluid blowing ports, it is possible to divide the polishing surface into a finer range and make those portions have a desired temperature distribution. This makes it possible to easily obtain a more uniform polishing profile.

  According to the invention described in claim 4 of the present application, the flow rate adjusting means for individually adjusting the flow rate of the fluid blown from the plurality of fluid outlets and / or the temperature of the fluid blown from the plurality of fluid outlets are individually adjusted. Since the temperature adjusting means is provided, a local portion of the polishing surface can have a desired temperature distribution, and a more uniform polishing profile can be easily obtained.

  According to invention of Claim 5 of this application, the number of the fluid outlets which adjusts the number of the fluid outlets which blow off the fluid among several fluid outlets, and / or the fluid to the grinding | polishing surface of each fluid outlet Since the spray position adjusting means for adjusting the spray position is provided, the local portion of the polishing surface can have a desired temperature distribution, and a more uniform polishing profile can be easily obtained.

  According to the invention described in claim 6 of the present application, the polishing surface temperature control means is based on the measurement result of the polishing surface temperature distribution measurement means, the flow rate adjustment means, the temperature adjustment means, the outlet number adjustment means, the blowing position adjustment. Since the polishing surface is controlled to have a predetermined temperature distribution by controlling the flow of fluid using at least one of the means, the temperature distribution of the target polishing surface is accurately based on the temperature distribution of the actual polishing surface. And a more uniform polishing profile can be obtained.

  According to the invention of claim 7 of the present application, when performing the polishing process, the temperature distribution of the polishing surface is controlled to a predetermined temperature distribution, and the polishing rate of each part of the surface to be polished of the substrate is controlled. Even in a CMP process in which the polishing rate of the surface to be polished is highly dependent on the polishing surface temperature, each part of the surface to be polished can be polished at a desired polishing rate without reducing the surface pressure of the entire surface to be polished. A uniform polishing profile can be obtained while maintaining a high polishing rate on the surface to be polished.

  According to the invention described in claim 8 of the present application, the polishing step includes a first polishing step in which polishing is performed by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution by the polishing surface temperature control means, and the polishing surface temperature. Since it comprises a second polishing step in which polishing is performed without controlling the temperature distribution of the polishing surface by the control means, the temperature distribution of the polishing surface is controlled in the first polishing step to obtain a uniform polishing profile. On the other hand, in the second polishing step, it is possible to perform polishing while suppressing the occurrence of problems such as drying of the polished surface by controlling the temperature distribution of the polished surface.

  According to invention of Claim 9 of this application, a 1st grinding | polishing process is a process of blowing out a fluid toward a grinding | polishing surface with the fluid blowing mechanism with which a grinding | polishing surface temperature control means is equipped, and 2nd Since the polishing process is a process in which the blowing of the fluid by the fluid blowing mechanism is stopped and polishing is performed, drying of the polishing surface in the second polishing process can be suppressed, so that agglomeration of abrasive grains and the like can be suppressed and polishing is performed. It is possible to prevent the occurrence of defects such as scratches on the surface.

  According to invention of Claim 10 of this application, a grinding | polishing process is a 1st grinding | polishing process which performs grinding | polishing by controlling the temperature of this grinding | polishing surface to predetermined temperature distribution by a grinding | polishing surface temperature control means, and a grinding | polishing surface. Since the temperature control means comprises a second polishing step for performing polishing by controlling the temperature distribution of the polishing surface to a temperature distribution higher than the temperature distribution in the first polishing step, polishing in the second polishing step Since the rate is lower than the polishing rate of the first polishing step, the end point of the polishing step in the second polishing step can be accurately detected, and improvement in the accuracy of the polishing end point detection can be expected.

  According to invention of Claim 11 of this application, a 1st grinding | polishing process is a process which blows and polishes a predetermined flow volume of fluid toward a grinding | polishing surface with a fluid blowing mechanism, A 2nd grinding | polishing process Since the polishing is performed by blowing out the fluid having a flow rate smaller than the flow rate of the fluid in the first step by the fluid blowing mechanism, the polishing rate of the second polishing step is changed to the first polishing rate by a simple process change. By lowering than the polishing rate of the process, the end point of the polishing process in the second polishing process can be accurately detected. In addition, drying of the polished surface in the second polishing step can be suppressed.

  According to the invention described in claim 12 of the present application, the polishing step is a first polishing step of blowing a gas that is not humidified toward the polishing surface by the fluid blowing mechanism, and a humidification toward the polishing surface by the fluid blowing mechanism. The second polishing step of blowing out the generated gas, so that drying of the polished surface in the second polishing step can be suppressed, so that aggregation of abrasive grains and the like can be suppressed, and defects such as scratches on the polished surface can be prevented. Occurrence can be prevented.

  According to the invention described in claim 13 of the present application, since the time of the first polishing step occupies more than half of the entire polishing step, polishing can be performed without reducing the polishing rate except in the vicinity of the polishing end point. it can.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic side view showing the configuration of the polishing apparatus according to the first embodiment of the present invention. The polishing apparatus shown in the figure includes a circular flat plate-like polishing table (turn table) 1 supported by a rotating shaft 3 and installed so as to rotate in a horizontal plane, and a polishing cloth 2 is attached to the upper surface of the polishing table 1. In addition, a polished surface 8 is formed. A top ring 4 that holds the substrate W is installed on the upper part of the polishing table 1. The top ring 4 is pivotally attached to the lower end of the top ring rotating shaft 5, and the top ring rotating shaft 5 is a polishing table shown in the figure by a top ring swinging arm 6 that swings (turns) around the swing shaft 7. 1 is supported in a swingable manner between a polishing position on the substrate 1 and a substrate delivery position (not shown) on the side of the polishing table 1. Further, the top ring 4 can be moved up and down with respect to the polishing surface 8 together with the top ring rotating shaft 5 by elevating means (not shown), and descends toward the polishing surface 8 so that the surface 9 to be polished of the substrate W is lowered. While being brought into pressure contact with the polishing surface 8 with a predetermined pressure, the surface 9 to be polished is separated from the polishing surface 8 by being raised. A polishing liquid supply nozzle 10 that supplies a polishing liquid such as a slurry toward the polishing surface 8 is installed above the polishing table 1.

  The polishing apparatus includes polishing surface temperature control means 20 that controls the polishing surface 8 that contacts the surface 9 to be polished of the substrate W to have a predetermined temperature distribution. The polishing surface temperature control means 20 is installed at a position adjacent to the top ring 4 on the polishing table 1, and a fluid blowing mechanism 30 that blows fluid (gas in this embodiment) toward the polishing surface 8, and the polishing surface 8. The polishing surface temperature distribution measuring means 40 for measuring the temperature distribution of the above and a controller 50 are provided. Hereinafter, each component of the polishing surface temperature control means 20 will be described in order.

  2A and 2B are diagrams for explaining the configuration of the fluid blowing mechanism 30. FIG. 2A is a view of the polishing table 1 as viewed from above, and FIG. 2B is a view of the polishing table 1 as viewed from the side. . In FIG. 2B, only a part of the fluid blowing mechanism 30 is shown. FIG. 3 is a diagram showing an overall configuration of the fluid blowing mechanism 30. As shown in FIG. 2, the fluid blowing mechanism 30 is provided on the side of the top ring 4 on the polishing table 1 (specifically, the polishing surface of the portion that contacts the surface to be polished 9 of the substrate W due to the rotation of the polishing table 1). A plurality of (five in the figure) blowing nozzles (fluid outlets) 32 that are installed radially above the side surface of the top ring 4 and that are installed on the side portion above the position where the 8 moves and passes. I have. Each blowing nozzle 32 opens toward the polishing surface 8 and blows gas to different positions on the polishing surface 8.

  As shown in FIG. 3, each blowing nozzle 32 is connected to a gas source 34 to which a gas such as compressed air or nitrogen gas is supplied via each pipe 33, and blows out the gas supplied from the gas source 34. It is configured. Each pipe 33 is provided with a needle valve 35 which is a flow rate adjusting means for individually adjusting the flow rate of the gas blown from each blowing nozzle 32 and a flow meter 36 for measuring the flow rate. The measurement value of each flow meter 36 is input to the controller 50, and each needle valve 35 is configured to operate according to a command from the controller 50.

  Each pipe 33 is provided with a temperature adjusting means 37 such as a heater or a cooler for individually adjusting the temperature of the gas blown from each blowing nozzle 32. Further, spray position adjusting means (not shown), which is a mechanism for arbitrarily changing the position on the polishing surface 8 to which the gas discharged from each blow nozzle 32 is blown, by individually changing the posture of each blow nozzle 32. Is installed. The temperature adjusting means 37 and the spray position adjusting means are also configured to operate according to a command from the controller 50. In addition, when the gas dried from each blowing nozzle 32 is blown onto the polishing surface 8, the polishing surface 8 is dried and the slurry is solidified, and the surface 9 to be polished of the substrate W may be damaged. Thus, there is provided a humidifying mechanism 38 for humidifying the gas blown out from each of the blowout nozzles 32. Although not shown, a humidifier, a spray nozzle, or the like may be installed in the vicinity of the blowout nozzle 32 to prevent the polishing surface 8 from drying.

  In this embodiment, the polishing surface temperature distribution measuring means 40 is a thermography 40 that measures the temperature distribution of the polishing surface 8 (the temperature distribution of the portion in contact with the surface 9 to be polished), as shown in FIG. The measurement result of the temperature distribution of the polishing surface 8 by the thermography 40 is configured to be input to the controller 50. As the polishing surface temperature distribution measuring means 40, a plurality of radiation thermometers for measuring the temperature of each part on the polishing surface 8 can be used in addition to the thermography 40 shown in FIG.

  The controller 50 is electrically connected to the thermography 40 so as to input measurement data and to output a command to the fluid blowing mechanism 30. In addition, the controller 50 stores data of the polishing profile of the surface 9 to be polished in a state where the temperature control of the polishing surface 8 is not performed, and the optimal gas blowing flow rate from each blowing nozzle 32. A polishing surface temperature control program 51 is stored which controls the temperature distribution of the polishing surface by automatically determining the number of blow nozzles 32 for blowing gas, the number of blow nozzles 32 for blowing gas, and the blow direction (spray position) of each blow nozzle 32. ing.

  Next, the polishing process by the polishing apparatus having the above configuration will be described. The top ring swing arm 6 swings the top ring 4 to the polishing position on the polishing table 1. Then, the polishing table 1 is rotated around the rotating shaft 3, the top ring 4 is rotated around the top ring rotating shaft 5, and the slurry is supplied from the abrasive liquid supply nozzle 10 to the polishing surface 8, while lifting and lowering means. The top ring 4 is lowered, and the surface 9 to be polished of the substrate W held on the lower end surface of the top ring 4 is brought into press contact with the polishing surface 8. Thus, the surface 9 to be polished of the substrate W is polished by the relative movement of the surface 9 and the polishing surface 8.

  At that time, the thermography 40 measures the temperature distribution of the polishing surface 8 being polished, and inputs this measurement data to the controller 50. The polishing surface temperature control program 51 is based on the measurement data of the temperature distribution and the data of the polishing profile of the surface 9 to be polished in a state where the temperature control of the polishing surface 8 is not performed, which is stored in the controller 50. The amount of heating / cooling of the polishing surface 8 required to make the polishing rate of the surface 9 to be polished uniform is calculated, and the optimum blowing flow rate, blowing temperature, and blowing position of the gas from each blowing nozzle 32 are determined. Based on the determination result, the controller 50 outputs to the fluid blowing mechanism 30 the valve opening degree of each needle valve 35, the set temperature of each temperature adjusting means 37, and the command of the blowing position by each blowing position adjusting means, The blowing flow rate, blowing temperature, and blowing position of each blowing nozzle 32 are individually adjusted to blow gas onto the polishing surface 8. Thereby, the polishing surface 8 can be controlled to a predetermined temperature distribution, the polishing rate of the surface 9 to be polished that contacts the polishing surface 8 can be made uniform, and the surface 9 to be polished can be flattened.

  Here, when adjusting the blowing flow rate of each blowing nozzle 32, if one of the needle valves 35 is completely closed and the blowing from the blowing nozzle 32 is stopped, the number of blowing nozzles 32 that blow out the gas is adjusted. can do. In addition, each element of the gas blowing flow rate, the blowing temperature, and the blowing position described above may be configured not to be all of them but to control the temperature distribution of the polishing surface 8 by controlling any one of them. .

  According to the polishing apparatus having the above configuration, since the polishing surface temperature control means 20 is provided, the polishing surface 8 in contact with the surface 9 to be polished can have a desired temperature distribution, so that the polishing rate of the surface 9 to be polished is the polishing surface. Even in the CMP process highly dependent on the temperature of 8, the polishing rate of each part of the surface 9 to be polished can be freely controlled. Accordingly, it is possible to realize the planarization of the surface 9 to be polished while maintaining a high polishing rate of the surface 9 to be polished and maintaining good productivity without reducing the surface pressure of the entire surface 9 to be polished. Further, the polishing surface temperature control means 20 includes a plurality of blowing nozzles 32 for blowing gas to each part of the polishing surface 8, and a mechanism for individually adjusting the gas blowing flow rate, blowing temperature, and blowing position of each blowing nozzle 32. Therefore, it is possible to control the temperature distribution of each section by dividing the polishing surface 8 into a target fine range. Therefore, the polishing rate of each part of the surface 9 to be polished can be precisely controlled, and the surface 9 to be polished can be flattened with high accuracy.

  Further, the above polishing process is divided into the first half polishing process (first polishing process) and the second half polishing process (second polishing process), and the fluid of the polishing surface temperature control means 20 is used in these first half and second half polishing processes. The substrate W may be polished by changing the gas flow rate from the blowing mechanism 30. As a specific example, in the first half of the polishing process, a predetermined flow rate of gas is blown out from the fluid blowing mechanism 30 to perform polishing while controlling the temperature of the polishing surface 8, while in the second half of the polishing process, compared to the first half of the polishing process. Polishing is performed by reducing the gas flow rate from the fluid blowing mechanism 30, or the gas blowing is completely stopped (that is, without controlling the temperature of the polishing surface 8 by the polishing surface temperature control means 20). Polish. As a result, the drying of the abrasive liquid on the polishing surface 8 in the latter polishing step can be suppressed, so that the aggregation of abrasive grains can be suppressed and the occurrence of defects such as scratches (polishing scratches) on the surface 9 to be polished can be prevented. Is possible. Similarly, in order to suppress the drying of the abrasive liquid on the polishing surface 8, polishing is performed by blowing a non-humidified gas from the fluid blowing mechanism 30 in the first half polishing step, while the humidifying mechanism 38 is used in the second polishing step. Alternatively, polishing may be performed by blowing a gas or a mist-like gas-liquid mixed fluid humidified by a humidifier or a spray nozzle.

  In the polishing process in this polishing apparatus, even if a defect such as a scratch occurs on the surface 9 to be polished of the substrate W, if the film to be polished on the surface 9 to be polished is thicker than the depth of the scratch, the substrate W It will not be defective. Accordingly, as described above, the polishing process is divided into the first half and the second half, and by changing the operation state of the fluid blowing mechanism 30 with these, if polishing is performed while preventing aggregation of abrasive grains in the second half polishing process, the final process is performed. Specifically, it becomes possible to obtain a substrate W having no defects such as scratches on the surface 9 to be polished. Therefore, the timing for switching from the first half polishing step to the second half polishing step is determined in consideration of the size of the aggregate of abrasive grains. For example, when the thickness of the polishing target film reaches about 50 nm in the first half polishing step, the second half polishing step is switched. The determination of the switching timing is specifically based on the output value of a film thickness detector (not shown) such as a torque current sensor, eddy current sensor or optical sensor provided on the polishing table 1 or the top ring 4. To do.

  Further, the timing of switching to the latter polishing process may be determined by the time distribution of the first and second polishing processes. For example, by making the polishing process in the latter half longer than the polishing process in the first half, the fluid blowing mechanism 30 in the polishing process in the latter half, which is more than half the time of the entire polishing process, than in the polishing process in the first half that is the remaining time. Polishing can be performed by reducing the flow rate of gas from the nozzle, or polishing can be performed by stopping the blowing of gas. On the other hand, the polishing step may be performed by blowing out the gas for a time that is half or more of the entire polishing time, and stopping the blowing of the gas when the vicinity of the polishing end point is reached. Here, the case where the polishing process is divided into the first half and the second half of the polishing process has been described, but depending on the case, the polishing process may be divided into three or more stages, or even when divided into two stages, An etching process of the substrate W may be employed instead of the latter polishing process.

  Further, as described above, in the latter polishing step, if the polishing is performed by reducing the gas blowing flow rate than in the first half polishing step, or if the polishing is stopped by stopping the gas blowing, By reducing the cooling effect of 8, the temperature distribution of the polishing surface 8 becomes a temperature distribution higher than the temperature distribution of the polishing process in the first half. As a result, the polishing rate of the surface to be polished 9 is reduced. However, if the polishing rate is reduced at the end of polishing, the end point of the polishing process can be detected more accurately. This leads to improved accuracy. In this way, polishing is performed by reducing the gas flow rate in the latter half of the polishing process, or polishing is performed by stopping the blowing of gas, so that the temperature distribution of the polishing surface 8 is made higher than the temperature distribution of the first half of the polishing process. However, if the temperature distribution is higher, it is possible to achieve an effect that the control for causing the substrate W to be polished to reach the ideal polishing end point value can be easily and reliably performed.

[Second Embodiment]
A second embodiment of the present invention will be described. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In addition, matters other than those described below are the same as those in the first embodiment. The same applies to other embodiments. FIG. 4 is a view for explaining the configuration of the fluid blowing mechanism 30-2 provided in the polishing apparatus according to the present embodiment. FIG. 4A is a view of the polishing table 1 viewed from above, and FIG. b) is a view from the side. In FIG. 5B, only a part of the fluid blowing mechanism 30-2 is shown. FIG. 5 is a diagram showing an overall configuration of the fluid blowing mechanism 30-2. The polishing apparatus according to this embodiment includes a fluid blowing mechanism 30-2 having another configuration shown in FIGS. 4 and 5 in place of the fluid blowing mechanism 30 provided in the polishing apparatus according to the first embodiment.

  As shown in FIG. 5, the fluid blowing mechanism 30-2 is provided with a blower 43 driven by a motor 42 at one end of a blower pipe 41, and an intake port 44 that opens to the outside of the polishing apparatus is provided on the suction side of the blower 43. It has been. The blower 43 is operated / stopped by a command from the controller 50. On the other hand, an air filter 45 is installed in the middle of the blower pipe 41, and a blow-out portion 46 is provided at the other end of the blower pipe 41. As shown in FIG. 4, the blowout portion 46 is disposed at one side position of the top ring 4 on the polishing table 1 (the same position as the fluid blowout port 31 of the first embodiment). The blowout portion 46 is divided into a plurality (four in the figure) of blowout ports 47, and the blowout ports 47 are arranged radially so as to surround the side surface of the top ring 4. Each outlet 47 is configured to open toward the polishing surface 8 and to blow gas to different positions on the polishing surface 8. Further, a throttle valve 48 that individually adjusts the opening degree of the flow path to each outlet 47 is installed at a portion of the outlet 46 that branches from the blower pipe 41 to each outlet 47. Each throttle valve 48 is configured to open and close in response to a command from the controller 50. Although not shown in the present embodiment, a humidifying mechanism for humidifying the gas blown out from each outlet 47 is provided in order to prevent the polishing surface 8 from drying, or a humidifier or a spray nozzle is provided in the vicinity of the outlet 46. Etc. may be installed.

  In this polishing apparatus, when polishing the surface 9 to be polished, the air blower 43 is operated to blow air sucked from the outside of the polishing apparatus onto the polishing surface 8 to control the temperature distribution of the polishing surface 8. At that time, similarly to the polishing apparatus of the first embodiment, the heating / cooling amount of the polishing surface 8 necessary for making the polishing rate of the surface 9 to be polished uniform from the measurement result of the temperature distribution of the polishing surface 8 by the thermography 40. Is calculated and the optimum gas flow rate from each air outlet 47 is determined. Based on the determination result, the controller 50 issues a command for the opening of the throttle valve 48, changes the opening of the flow path leading to each outlet 47, and individually adjusts the gas flow rate from each outlet 47. To do. Thereby, the polishing surface 8 is controlled to a predetermined temperature distribution. At this time, it is also possible to adjust the number of outlets 47 through which gas blows out by completely closing any of the throttle valves 48.

[Third Embodiment]
FIG. 6 is a view for explaining the configuration of a polishing apparatus according to a third embodiment of the present invention. FIG. 6 (a) is a view of the polishing table 1 as viewed from above, and FIG. It is the figure seen from the direction. The polishing apparatus of the present embodiment replaces the fluid blowing mechanism 30 provided in the polishing apparatus of the first embodiment, and as a means for controlling the temperature distribution of the polishing surface, cooling that rolls while bringing the side surface into contact with the polishing surface 8. A heating roller 60 is installed. The cooling and heating roller 60 includes a substantially conical contact portion 61, and the rotation shaft 62 is centered in a state where the side surface 61 a of the contact portion 61 is in contact with the polishing surface 8 due to the movement of the polishing surface 8 as the polishing table 1 rotates. It is comprised so that it may roll. The contact portion 61 is made of a metal material such as stainless steel, titanium, or an aluminum alloy subjected to corrosion resistance treatment. And each part of the side surface 61a of the contact part 61 is comprised with the multiple types of metal material from which a heat absorption rate mutually differs so that the grinding | polishing surface 8 to contact can be made into predetermined temperature distribution. Although not shown in the figure, a vertical movement mechanism for moving the cooling and heating roller 60 up and down relative to the polishing surface 8 to bring the side surface 61a of the contact portion 61 into contact with and away from the polishing surface 8 is provided. The vertical movement mechanism operates according to a command from the controller 50.

  In this polishing apparatus, when polishing the surface 9 to be polished, polishing is performed while the cooling heating roller 60 is brought into contact with the polishing surface 8 and rolling, so that each part of the side surface 61a of the contact portion 61 and the polishing surface 8 are polished. Heat exchange is performed with each part, and the temperature distribution of the polishing surface 8 is controlled. At that time, similarly to the polishing apparatus of the first embodiment, from the measurement result of the temperature distribution of the polishing surface 8 by the thermography 40, the heating and cooling of the polishing surface 8 necessary for making the polishing rate of the surface 9 to be polished uniform. Determine the amount. Based on this determination result, the cooling and heating roller 60 is moved up and down to adjust the contact time of the contact portion 61 with the polishing surface 8. As a result, the polishing surface 8 has a predetermined temperature distribution.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. It should be noted that any shape, structure, and material not directly described in the specification and drawings are within the scope of the technical idea of the present invention as long as the effects and advantages of the present invention are exhibited. For example, the fluid blown out from the fluid blowing mechanism 30 is not limited to gas, but may be liquid, mist-like gas-liquid mixed fluid, or the like. Further, even in the case of gas, the type is not limited to the above compressed air or nitrogen gas, and other types of gas can be used depending on the purpose. Further, the number and shape of the blowout nozzles 32 and blowout ports 47 of the fluid blowout mechanism 30 are not limited to those shown in the above embodiment, and other numbers are used to configure the polishing surface 8 to have a predetermined temperature distribution. It can also be a shape. Further, the specific configuration of the polishing apparatus is not limited to those shown in the above embodiments.

  Next, an embodiment of the present invention will be described with reference to FIG. FIG. 6B shows the case where the substrate W is polished without heating / cooling the polishing surface 8 on the polishing table 1 (without controlling the temperature distribution of the polishing surface 8) and according to the present invention. Comparison of the polishing profile of the surface to be polished 9 of the substrate W with the case where the polishing is performed while cooling a predetermined region (region denoted by symbol A) on the polishing surface 8 shown in FIG. It is a graph which shows. In this case, the cooling of the polishing surface 8 was performed by the polishing apparatus according to the above-described embodiment, in which the gas was blown out only from the blowing nozzle 32 that blows the gas onto the portion A on the polishing surface 8. In the graph, the horizontal axis represents the measurement position on the surface 9 to be polished (indicated by the distance from the center of the surface 9 to be polished), and the vertical axis represents the polishing rate. As can be seen from this polishing profile, when polishing is performed without controlling the temperature distribution of the polishing surface 8, the polishing rate becomes closer to the outer periphery of the surface 9 to be polished due to the influence of the surface pressure distribution on the surface 9 to be polished. Although there is a tendency to decrease, when the polishing is performed by controlling the temperature distribution of the polishing surface 8 by cooling the portion of the polishing surface 8 in contact with the vicinity of the periphery of the surface 9 to be polished, the vicinity of the periphery of the surface 9 to be polished The polishing rate can be increased. As a result, a uniform polishing rate can be obtained over the entire surface 9 to be polished, and the surface 9 to be polished can be flattened.

It is a schematic side view which shows the structural example of the grinding | polishing apparatus concerning 1st Embodiment of this invention. FIG. 4A is a view for explaining a detailed configuration of the fluid blowing mechanism 30. FIG. 1A is a view of the polishing table 1 as viewed from above, and FIG. 2B is a view of the polishing table 1 as viewed from the side. FIG. 2 is a diagram showing an overall configuration of a fluid blowing mechanism 30. FIG. 4 is a view showing a configuration of a fluid blowing mechanism 30-2 included in a polishing apparatus according to a second embodiment of the present invention. FIG. 4A is a view of the polishing table 1 as viewed from above. Figure (b) is a view from the side. FIG. 5 is a diagram illustrating an overall configuration of the fluid blowing mechanism 30-2. FIG. 6 is a view for explaining the configuration of a polishing apparatus according to a third embodiment of the present invention. FIG. 6 (a) is a view of the polishing table 1 as viewed from above, and FIG. It is the figure seen from the side. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining an embodiment of the present invention, in which FIG. 1A is a view of a polishing table 1 viewed from above, and FIG. 1B shows a polishing profile of a surface to be polished of a substrate W; It is a graph.

Explanation of symbols

1 Polishing table 2 Polishing cloth (polishing pad)
DESCRIPTION OF SYMBOLS 3 Rotating shaft 4 Top ring 5 Top ring rotating shaft 6 Top ring oscillating arm 7 Oscillating shaft 8 Polishing surface 9 Surface to be polished 10 Polishing liquid supply nozzle 20 Polishing surface temperature control means 30 Fluid blowing mechanism 30-2 Fluid blowing mechanism 32 Blowing nozzle (fluid outlet)
33 Piping 34 Gas source 35 Needle valve (flow rate adjusting means)
36 Flow meter 37 Temperature adjusting means 38 Humidification mechanism 40 Thermography (polishing surface temperature distribution measuring means)
41 Blower pipe 42 Motor 43 Blower 44 Air inlet 45 Air filter 46 Blowing section 47 Air outlet (fluid air outlet)
48 Throttle valve (flow rate adjusting means)
50 Controller 51 Polishing surface temperature control program 60 Cooling and heating roller 61 Contact portion 61a Side surface 62 Rotating shaft

Claims (13)

A substrate holding mechanism for holding the substrate and a polishing table having a polishing surface are provided. The polishing surface of the substrate held by the substrate holding mechanism is brought into contact with the polishing surface of the polishing table, and the relative movement between the polishing surface and the polishing surface is performed. In a polishing apparatus for polishing a surface to be polished,
A polishing surface temperature control means for controlling the temperature distribution of the polishing surface of the polishing table is provided, the temperature distribution of the polishing surface is controlled to a predetermined temperature distribution by the polishing surface temperature control means, and each part of the surface to be polished of the substrate is controlled. A polishing apparatus for controlling a polishing rate. The polishing apparatus according to claim 1, wherein
The polishing apparatus according to claim 1, wherein the polishing surface temperature control means includes a fluid blowing mechanism that blows fluid toward the polishing surface of the polishing table to make the polishing surface have a predetermined temperature distribution. The polishing apparatus according to claim 2, wherein
The polishing apparatus according to claim 1, wherein the fluid blowing mechanism includes a plurality of fluid blowing ports. The polishing apparatus according to claim 3, wherein
It is characterized by comprising flow rate adjusting means for individually adjusting the flow rate of the fluid blown from the plurality of fluid outlets and / or temperature adjusting means for individually adjusting the temperature of the fluid blown from the plurality of fluid outlets. Polishing equipment. The polishing apparatus according to claim 3 or 4,
An outlet number adjusting means for adjusting the number of fluid outlets for blowing out the fluid among the plurality of fluid outlets, and / or a blowing position adjusting means for adjusting the spray position of the fluid to the polishing surface of each fluid outlet. A polishing apparatus comprising the polishing apparatus. The polishing apparatus according to claim 4 or 5,
A polishing surface temperature distribution measuring means for measuring the temperature distribution of the polishing surface of the polishing table;
The polishing surface temperature control means uses at least one of the flow rate adjustment means, temperature adjustment means, outlet number adjustment means, and spray position adjustment means based on the measurement result of the polishing surface temperature distribution measurement means. A polishing apparatus, wherein the polishing surface is controlled to have a predetermined temperature distribution by controlling blowing. A polishing step of bringing the polishing surface of the substrate into contact with the polishing surface and polishing the polishing surface by relative movement of the polishing surface and the polishing surface;
A polishing method characterized in that when performing the polishing step, the polishing rate of each part of the surface to be polished of the substrate is controlled by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution. A polishing step of bringing the polishing surface of the substrate into contact with the polishing surface and polishing the polishing surface by relative movement of the polishing surface and the polishing surface;
The polishing step is a first polishing step in which polishing is performed by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution by a polishing surface temperature control means for controlling the temperature distribution of the polishing surface;
A second polishing step of polishing without controlling the temperature distribution of the polishing surface by the polishing surface temperature control means;
A polishing method comprising: The polishing method according to claim 8, wherein
The first polishing step is a step of performing polishing by blowing a fluid toward the polishing surface with a fluid blowing mechanism provided in the polishing surface temperature control means to control the temperature distribution of the polishing surface,
The polishing method, wherein the second polishing step is a step of performing polishing by stopping the blowing of fluid by the fluid blowing mechanism. A polishing step of bringing the polishing surface of the substrate into contact with the polishing surface and polishing the polishing surface by relative movement of the polishing surface and the polishing surface;
The polishing step is a first polishing step of performing polishing by controlling the temperature of the polishing surface to a predetermined temperature distribution by a polishing surface temperature control means for controlling the temperature of the polishing surface;
A second polishing step of performing polishing by controlling the temperature distribution of the polishing surface to a temperature distribution higher than the temperature distribution in the first polishing step by the polishing surface temperature control means;
A polishing method comprising: The polishing method according to claim 10, wherein
The first polishing step is a step of performing polishing by blowing a fluid at a predetermined flow rate toward the polishing surface with a fluid blowing mechanism provided in the polishing surface temperature control means,
The polishing method is characterized in that the second polishing step is a step of performing polishing by blowing out a fluid having a flow rate smaller than the flow rate of the fluid in the first step by the fluid blowing mechanism. A polishing step of bringing the polishing surface of the substrate into contact with the polishing surface and polishing the polishing surface by relative movement of the polishing surface and the polishing surface;
The polishing step is performed by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution by blowing a non-humidified gas toward the polishing surface by a fluid blowing mechanism that blows fluid toward the polishing surface. A first polishing step to be performed;
A second polishing step of performing polishing by controlling the temperature distribution of the polishing surface to a predetermined temperature distribution by blowing a gas humidified toward the polishing surface by the fluid ejection mechanism;
A polishing method comprising: The polishing method according to any one of claims 8 to 12,
A polishing method characterized in that the time of the first polishing step occupies more than half of the entire polishing step.

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