TWI570791B - Polishing apparatus and substrate holding apparatus - Google Patents

Description

Grinding device and substrate holding device

The present invention relates to a polishing apparatus and method, and more particularly to a polishing apparatus and method for polishing a polished object (substrate), such as a semiconductor wafer, to a flat mirror finish.

In recent years, semiconductors have become more integrated and have higher density requirements for wiring patterns or interconnects and more and more interconnect layers. The interconnection of a plurality of complex lines in a smaller circuit creates more steps, resulting in an irregular surface on the lower interconnect layer. The increase in the number of interconnect layers makes the film coating performance (step coverage) worse, and the more the film is covered by the step, the worse the configuration becomes. Therefore, in order to obtain a better level of interconnection, it is necessary to have improved step coverage and appropriate surface smoothing. Secondly, since the depth of focus of the photolithographic optical system is small in the miniaturization of the lithography process, the surface of the semiconductor device needs to be flattened so that the surface of the semiconductor device is irregular. The ladder can fall within the depth of focus.

Therefore, in semiconductor manufacturing, surface planarization is becoming more and more important for semiconductor devices. One of the most important planarization techniques is chemical mechanical polishing (CMP). Therefore, chemical mechanical polishing machines have been used to planarize the surface of semiconductor wafers. In a chemical mechanical polishing machine, when a polishing liquid containing abrasive particles (for example, cerium oxide (SiO ₂ )) is supplied onto an abrasive surface (for example, a polishing pad), a substrate (for example, a semiconductor wafer) is brought to and The abrasive surface is in sliding contact such that the substrate is ground.

A polishing apparatus of this type includes a polishing table having an abrasive surface composed of a polishing pad, and a substrate holding device called a top ring or a polishing head to hold a substrate. , for example, semiconductor wafers. When the semiconductor wafer is polished by the polishing apparatus, the semiconductor wafer is held by the substrate holding device and pressed against the polishing surface under a predetermined pressure. At this time, the polishing table and the substrate holding device move relative to each other to make the semiconductor wafer slidingly contact with the polishing surface, so that the surface of the semiconductor wafer is polished to a degree of flat mirror polishing.

In such a polishing apparatus, if the pressing force applied between the polished semiconductor wafer and the polishing surface of the polishing pad is not uniformly applied to the entire surface of the semiconductor wafer, the surface of the semiconductor wafer is on different regions, It is insufficiently or excessively ground depending on the applied pressing force. It is customary to utilize a pressure chamber to evenly apply the compressive force applied to the semiconductor wafer, and the pressure chamber is formed by an elastic membrane located below the substrate holding device, and a fluid such as compressed air is applied to the pressure chamber. And, under the fluid pressure, the semiconductor wafer is pressed against the polishing surface of the polishing pad via the elastic film.

On the other hand, the film formed on the surface of the semiconductor wafer of the object to be polished has different thickness depending on the radial position of the semiconductor wafer due to the characteristics of the method or device for forming the film. In particular, the film formed on the surface of the semiconductor wafer has an initial film thickness distribution in its radial direction. Therefore, as described above, the substrate holding device uniformly presses the entire surface of the semiconductor wafer to polish the semiconductor wafer, and the entire surface of the semiconductor wafer is uniformly polished, thereby forming the initial film thickness on the surface of the semiconductor wafer. The distribution cannot be corrected. For example, as disclosed in Japanese Laid-Open Patent Publication No. 2006-128582, there is a polishing apparatus having a plurality of pressure chambers therein which are formed of an elastic film on the surface of a semiconductor wafer and supplied to The pressures of the pressurized fluid, such as compressed air, in each pressure chamber are independently controlled to control the various pressures supplied to the semiconductor wafer in various regions on the semiconductor wafer. Therefore, the pressing force for pressing the semiconductor wafer against the grinding surface in a grinder has a greater pressing force in the thicker film region than in the thinner film region, and the polishing rate in the thicker film region. The polishing rate is selectively increased, and the entire semiconductor wafer surface can be polished uniformly without depending on the film thickness distribution when the film is formed.

When a substrate (e.g., a semiconductor wafer) is ground by a grinder having the structure described above, the substrate is subjected to a relatively abrasive pressure and pressed against the abrasive surface of the polishing pad and brought into sliding contact with the abrasive surface. As a result, the temperature at which the substrate and the polishing pad contact surface (i.e., the polishing temperature) rise. As described above, it is important to control the grinding pressure for the purpose of improving the polishing performance. However, it is also important to measure and control the grinding temperature for the purpose of improving the grinding performance. In particular, since the polishing pad contains a resin material such as foamed polyurethane, the polishing temperature changes the rigidity of the polishing pad and affects the planarization characteristics of the substrate. In addition, since chemical mechanical polishing (CMP) is a polishing method that utilizes a chemical reaction between a polishing liquid (polishing slurry) and a surface to be polished of a substrate, the polishing temperature affects the chemical properties of the slurry. Moreover, the polishing rate distribution changes with the polishing temperature so as to lower the yield rate or the polishing rate, thereby reducing the productivity of the mill. Furthermore, if there is a temperature distribution in the surface of the substrate, the polishing performance in the surface of the substrate will become uneven.

For example, Japanese Patent Publication No. 2002-301660 and No. 2005-268566 disclose the temperature of a substrate (e.g., a semiconductor wafer) during the grinding process. Further, as disclosed in Japanese Laid-Open Patent Publication No. 2006-332520, the temperature of the film for holding the semiconductor wafer is measured as a temperature for measuring a portion of the surface of the adjacent semiconductor wafer during the grinding process. Means.

As described above, in the Japanese Patent Publication Nos. 2002-301660, 2005-268566, and 2006-332520, the temperature of a substrate (for example, a semiconductor wafer) or a film for holding a semiconductor wafer is measured during the grinding process. temperature. Further, Japanese Patent Laid-Open Publication No. 2002-301660 discloses that, in order to measure the temperature of the substrate with high accuracy, the temperature of the substrate surface is measured by detecting two or more infrared wavelengths from the opposite side of the substrate. However, in the technique disclosed in Japanese Laid-Open Patent Publication No. 2002-301660, since the film forming the pressure chamber cannot be used as a method of pressing the substrate, uniform distribution of the polishing rate cannot be obtained. In addition, since the temperature measurement of the surface of the substrate to be polished is obtained by measuring the infrared rays passing through the substrate, the transmission condition of the infrared rays varies depending on the type of the film on the substrate, or if water droplets adhere to the opposite surface of the substrate. If the opposite surface of the upper or substrate is wet, a significant amount of infrared light will change, resulting in different measurements.

Further, Japanese Laid-Open Patent Publication No. 2005-268566 discloses the use of an open air bag having an open substrate holding surface for measuring the temperature of the substrate. In such an open air bag, the pressurized fluid leaks during the grinding process, and the water or the slurry enters the open portion of the air bag to hinder the accurate measurement of the temperature. Further, as disclosed in Japanese Laid-Open Patent Publication No. 2005-268566, when the temperature of the substrate is measured by a general-purpose infrared radiation type temperature, since the infrared rays pass through the tantalum wafer, the infrared radiation type thermometer only has a metal film. Wafers are not suitable for measuring the temperature of other objects, and, even if a closed air bag is used, and the air bag made of a material that allows electromagnetic rays to pass through, there is still a certain degree of airbag even if it is composed of a film. The hindrance to electromagnetic radiation transmission cannot measure the temperature of the substrate with high accuracy.

In addition, Japanese Laid-Open Patent Publication No. 2006-332520 discloses a technique for measuring a film temperature for holding a semiconductor wafer as a means for measuring a temperature of a surface to be polished adjacent to a semiconductor wafer. However, in the technique disclosed in Japanese Laid-Open Patent Publication No. 2006-332520, since the temperature sensor is attached to the film, when the film is replaced due to loss, the temperature sensor needs to be replaced at the same time. Therefore, this technique requires a very expensive structure, and the wiring work of the temperature sensor is similar to the case where the film is replaced each time, thereby reducing the throughput.

The inventors of the present invention have intensively studied the techniques disclosed in Japanese Laid-Open Patent Publication No. 2006-128582, No. 2002-301660, No. 2005-268566, No. 2006-332520, and the like. As a result, it has been found that although it is desirable to measure a substrate (e.g., a semiconductor wafer) during the polishing process, if a film for forming a pressure chamber cannot be used, a serious problem can be caused and the polishing performance of the polishing apparatus cannot be maintained. Therefore, it has been found that the optimum is to estimate the temperature of the substrate during the grinding process by measuring the temperature of an element (e.g., a film) adjacent to the substrate on the premise of using the film forming the pressure chamber.

The inventors of the present invention attempted to estimate the temperature of the substrate from the temperature of the film forming the pressure chamber during the grinding process by using a non-contact infrared radiation thermometer, and then using several types of films. Mounted on the substrate holding device (top ring), repeating the heating and cooling of each substrate held by each film. Experiment with an infrared radiation thermometer and a thermocouple to measure the temperature of each film, and check the two measurements. relationship. As a result, it has been found that the measurement of the temperature of the film by the infrared radiation temperature and the measurement of the temperature of the film by the thermocouple are used, and the films of a certain type are substantially coincident with each other, while the films of other types are similar. There are differences between each other (as described later).

The inventors of the present invention analyzed the above-mentioned differences and found that since the surface of the film reflects infrared rays, the measured value is affected by the temperature of each component around the film, and thus the temperature of the film cannot be accurately measured by the infrared radiation thermometer. The film is produced by a mold in a forming process. Since the surface of the mold is usually mirror polished, the surface of the film also becomes a mirror surface with a small surface roughness. The upper surface of the film in a mirror state has a high infrared reflection coefficient. Therefore, if the infrared radiation temperature is measured at a position above the film, the measurement value is strongly affected by the infrared irradiation of the portion around the film, and thus the film temperature cannot be measured with high precision.

Furthermore, the inventors of the present invention have found that if the film temperature is measured by a non-contact infrared radiation thermometer, the temperature of the film cannot be measured with high precision due to condensation on the film.

The inventors of the present invention conducted various experiments and analyzed the results of the experiments in order to find out the cause of condensation on the film, and obtained the following knowledge: when the substrate is pressed against the polishing pad to be ground, the heat in the process will be a film. And the heating of the gas in the pressure chamber, thus causing an increase in temperature. After the substrate is polished, the substrate is removed from the substrate holding surface, and then the substrate holding surface is cleaned by the cleaning liquid during the cleaning process, and the film and the gas in the pressure chamber are cooled. Therefore, the film and the gas in the pressure chamber repeat the temperature rise and the temperature drop. In another aspect, the fluid passage into which the supply gas enters the pressure chamber is typically coupled to a pressure controller, a pressure relief valve, a vacuum source, and the like. In the case of a pressurized fluid, an inert gas (for example, nitrogen (N ₂ )) or dry air which removes moisture is usually used, so that condensation does not occur any more. However, when the substrate is fixed by the substrate holding device in a vacuum state, the pressure chamber becomes a vacuum to fix the substrate in a vacuum state. Therefore, when the substrate is started to be polished or the substrate is removed from the substrate holding device, the vacuum state is released by the atmospheric pressure exposed to the pressure chamber. When the fluid passage connecting the pressure chambers is switched from the vacuum state to the pressure chamber to the atmospheric pressure state, the air in the atmosphere in which the grinder is placed enters the fluid passage. Therefore, the air containing moisture enters the pressure chamber through the pressure release operation, and the air in the pressure chamber repeats the temperature rise and the temperature decrease, thereby causing condensation on the film. When the water droplets adhere to the upper surface of the film due to the condensation of the film, the infrared rays are partially irradiated with the amount of infrared rays of the water droplets, so that the temperature of the film cannot be measured with high accuracy by the infrared thermometer. Further, when the amount of water droplets caused by the condensation phenomenon increases, water accumulates in the pressure chamber and changes the pressure supplied to the substrate, resulting in failure to achieve stable polishing.

The present invention has been made in view of the above circumstances, and it is therefore an object of the present invention to provide a substrate holding device having a film which forms a pressure chamber which can control the temperature of a substrate such as a semiconductor wafer, and the temperature control method is used to estimate the polishing period. The temperature of the substrate.

Furthermore, another aspect of the present invention provides a polishing apparatus having such a substrate holding device.

In order to achieve the above object, a first aspect of the present invention provides a polishing apparatus for polishing a substrate, comprising: a polishing table having an abrasive surface, and a substrate holding device configured to fix the substrate and the substrate Press against the abrasive surface and the controller. The substrate holding device includes an elastic film configured to form a substrate holding surface in contact with the substrate, a carrier disposed above the elastic film, and at least one pressure chamber formed on the elastic film and the carrier And an infrared detector is configured to measure thermal energy from the elastic film; wherein the controller uses the measured value of the infrared detector to calculate a temperature estimate of the elastic film.

According to the present invention, a substrate such as a semiconductor wafer is held by an elastic film, and the substrate is pressed against the polishing surface to polish the substrate, and the thermal energy emitted from the elastic film is measured by an infrared detector, and then the controller The measured value of the infrared detector is used to calculate the temperature estimate of the elastic film. In this case, the correlation between the measured value of the infrared detector and the temperature of the elastic film is determined in advance by experiments, and then the correlation is used to calculate the estimated value of the elastic film temperature. . Since the elastic film constitutes the substrate holding surface to hold the substrate, the elastic film is the component most affected by the substrate temperature, and thus the temperature of the substrate can be indirectly estimated by estimating the temperature of the elastic film.

In a preferred aspect of the invention, the controller utilizes a temperature estimate of the elastic film to calculate a temperature estimate for the substrate.

According to the invention, the temperature estimate of the substrate is derived from the temperature estimate of the elastic film and is calculated by the controller. In this case, the correlation between the temperature of the elastic film and the temperature of the substrate is determined in advance by experiments, and then the correlation is utilized to calculate an estimate of the substrate temperature.

In a preferred aspect of the invention, the temperature estimate of the elastic film is utilized to vary the milling conditions.

According to the present invention, during the grinding, if the temperature estimation value of the elastic film or the temperature estimation value of the substrate is high, the polishing pressure is lowered by lowering the pressure of the pressure chamber to suppress the temperature of the substrate or the elastic film. rise. In addition, means for cooling and heating the abrasive surface disposed outside the substrate holding device may be utilized to perform temperature control of the entire abrasive surface or to perform temperature control of the portion of the abrasive surface corresponding to the pressure chamber being measured. As means for adjusting the temperature of the polishing surface, there are a device for bringing a medium into contact with the polishing surface to adjust the temperature of the polishing surface, a device for blowing a fluid onto the polishing surface, and the like.

In a preferred aspect of the invention, the temperature of the elastic film can be measured by measuring the amount of infrared energy emitted from the thermal energy of the elastic film of the object to be measured.

In order to achieve the above object, according to a second aspect of the present invention, there is provided a substrate holding device for fixing and pressing a substrate against a polishing surface, comprising: an elastic film configured to form a substrate holding surface and the substrate a contact, a carrier is disposed above the elastic film, at least one pressure chamber is formed between the elastic film and the carrier, and an infrared detector is configured to measure the elastic film. Thermal energy in which surface roughening is performed on the back side of the substrate holding surface of the elastic film.

According to the present invention, a substrate such as a semiconductor wafer is held by an elastic film and pressed against the polishing surface to polish the substrate, and the thermal energy emitted from the elastic film is measured by an infrared detector. Since the surface roughening process is performed on the back side of the substrate holding surface of the elastic film, the infrared reflectance of the back surface of the substrate holding surface of the elastic film is lowered, so that the infrared detector can be highly accurately measured. The thermal energy emitted from the elastic film is such that the temperature of the elastic film can be measured with high accuracy.

In order to achieve the above object, a third aspect of the present invention provides a substrate holding device including an elastic film configured to form a substrate holding surface to be in contact with the substrate, and a carrier disposed on the elastic film. Above, at least one pressure chamber is formed between the elastic film and the carrier, an infrared detector is configured to measure thermal energy from the elastic film, and a measuring instrument It is disposed on the back side of the substrate holding surface of the elastic film and is configured to measure the thermal energy except the elastic film portion.

According to the present invention, a substrate such as a semiconductor wafer is held by an elastic film and pressed against the polishing surface to polish the substrate, and the thermal energy emitted from the elastic film is measured by an infrared detector, and the elastic film is removed. The thermal energy outside the portion on the back side of the elastic film was measured by a measuring instrument. Then, the elastic film temperature estimation value or the substrate temperature estimation value is measured by the thermal energy measurement of the elastic film measured by the infrared detector, and the thermal energy measurement other than the elastic film portion is measured using the measuring instrument. The value is calculated. If the infrared rays emitted from the back side of the elastic film other than the elastic film portion are reflected by the elastic film and have a great influence on the infrared detector, the temperature of the elastic film or the temperature of the substrate cannot be detected by infrared rays. The measured values of the detector are estimated with high accuracy. Therefore, the elastic film temperature estimation value or the substrate temperature estimation value is calculated by using the infrared detector measurement value and the measurement value other than the elastic film portion measured by the measuring instrument.

In a preferred aspect of the invention, the measuring instrument measures the thermal energy of the carrier.

According to the present invention, the temperature of the carrier can be measured by measuring the thermal energy of the pressure chamber carrier together with the elastic film. If the infrared rays emitted from the carrier are reflected by the elastic film and have a great influence on the infrared detector, the temperature of the elastic film or the temperature of the substrate cannot be measured by the value of the infrared detector with high accuracy. Estimate. Therefore, the elastic film temperature estimation value or the substrate temperature estimation value is calculated by using the measured value of the infrared detector and the measured value of the vehicle temperature measured by the measuring instrument.

In a preferred aspect of the invention, the substrate holding device further includes a pressure sensor configured to measure the pressure of the pressure chamber.

According to the present invention, the pressure in the pressure chamber can be controlled by the pressure of the pressure chamber by a pressure sensor to control the desired pressure value. For example, the first pressure controller and the second pressure controller are coupled to the pressure chamber, and the two pressure controllers are set to the same pressure at the beginning of the grinding. When the substrate temperature estimate exceeds a predetermined temperature during grinding, the set pressure of the second pressure controller is lowered, and the set pressure of the first pressure controller is maintained at the same pressure. Thus, the pressurized fluid flows from the fluid passage in communication with the first pressure controller toward the fluid passage in communication with the second pressure controller, and the flow of the pressurized fluid cools the interior of the pressure chamber. At this time, the pressure in the pressure chamber is monitored by the pressure sensor, and when the pressure in the pressure chamber is greatly lowered and the control pressure is lower than the control pressure, the set pressure of the second pressure controller is increased, and The required pressure is created in the pressure chamber.

In a preferred aspect of the invention, the substrate holding device further includes a controller configured to utilize the infrared detector measurement and the measurement instrument to calculate an estimate of the temperature of the elastic film.

According to the present invention, the elastic film temperature estimation value is measured by the thermal energy measurement of the elastic film measured by the infrared detector, and the thermal energy measurement of the portion other than the elastic film is measured using the measuring instrument. Calculated by the person.

In a preferred aspect of the present invention, the elastic film temperature measurement value, the infrared detector measurement value (T ₁ ), and the measurement instrument measurement value (T ₂ ) of the complex array are prepared in advance, In a multivariate linear regression equation represented by (elastic film temperature estimate) = b ₀ + b ₁ × T ₁ + b ₂ × T ₂ to calculate the minimization (elastic film temperature measurement - elastic film temperature estimate ² ) Regression coefficients b ₀ , b ₁ and b ₂ ; and use the following equation: (elastic film temperature estimate) = b ₀ + b ₁ × (elastic film temperature measurement) + b ₂ × ( The measuring instrument is measured to calculate the elastic film temperature estimate.

In a preferred aspect of the invention, the controller utilizes an elastic film temperature estimate and a measurement instrument measurement to calculate a substrate temperature estimate.

According to the present invention, the substrate temperature estimation value is measured by the thermal energy measurement of the elastic film measured by the infrared detector, and the thermal energy measurement of the portion other than the elastic film measured by the measuring instrument. Calculated by the person.

In a preferred aspect of the invention, the substrate temperature measurement value, the elastic film temperature estimation value (T ₁ ), and the measurement instrument measurement value (T ₂ ) are prepared in advance, in one ( Substrate temperature estimation value = b ₀ + b ₁ × T ₁ + b ₂ × T ₂ represents the multiple linear regression equation to calculate the minimization (substrate temperature measurement - substrate temperature estimation) ² regression coefficient b ₀ , b ₁ and b ₂ ; and use the following equation: (substrate temperature estimate) = b ₀ + b ₁ × (elastic film temperature estimate) + b ₂ × (measurement instrument measured value) to calculate the substrate temperature estimate value.

In a preferred aspect of the present invention, at least two pressure chambers are formed between the elastic film and the carrier, and the infrared detector is disposed in at least one of the at least two pressure chambers. .

According to the present invention, in a substrate holding device having a plurality of pressure chambers, the infrared detector is disposed in a pressure chamber, and the pressure of each pressure chamber can be changed from the measurement result of the infrared detector, or The polishing conditions such as the operation of the polishing surface temperature adjusting device can be changed. Furthermore, two infrared detectors are respectively disposed in the two pressure chambers, and from the measurement results of the two infrared detectors, the temperature of the elastic film or the substrate temperature can be linearly interpolated (linear Interpolation) to estimate. In addition, each of the infrared detectors is disposed corresponding to all of the pressure chambers, and from the measurement results of the respective infrared detectors, the elastic film temperature or the substrate temperature corresponding to the positions of the respective pressure chambers can be estimated.

In a preferred aspect of the invention, the elastic film substrate holding surface on which the pressure chamber having the infrared detector is formed is not provided with an opening.

According to the present invention, since the elastic film substrate holding surface of the pressure chamber in which the infrared detector is disposed is not provided with an opening, when the substrate holding surface is cleaned, the cleaning liquid can be prevented from entering the infrared detecting device. The pressure chamber of the detector. Therefore, it is possible to prevent the water droplets from remaining on the back side of the elastic film, and thus the accuracy of the infrared detector can be ensured.

In a preferred aspect of the invention, the infrared detector comprises an infrared thermometer.

According to the present invention, the temperature of the elastic film can be measured by measuring the amount of infrared energy of the thermal energy emitted from the elastic film of the object to be measured.

In order to achieve the above object, according to a fourth aspect of the present invention, there is provided a polishing apparatus comprising: a polishing table having an abrasive surface; and a substrate holding device according to items 5 to 15 of the patent application.

In order to achieve the above object, according to a fifth aspect of the present invention, there is provided a polishing apparatus for polishing a substrate, comprising: a polishing table having an abrasive surface, the substrate holding device configured to hold the substrate and the substrate Pressed against the abrasive surface. The substrate holding device comprises an elastic film configured to form a substrate holding surface to be in contact with the substrate, a carrier disposed above the elastic film, and at least one pressure chamber formed on the elastic film and the carrier A first passageway between and with the pressure chamber, the first passage being connected only to a source of gas that is isolated from the atmosphere at which the grinding device is placed.

According to the present invention, when the pressure of the pressure chamber is increased from the vacuum state to the atmospheric pressure, a gas can be supplied to the pressure chamber from a gas source isolated from the atmosphere where the grinding device is placed. Therefore, air containing moisture can be prevented from entering the pressure chamber, so that no condensation of the elastic film occurs in the pressure chamber.

In order to achieve the above object, according to a sixth aspect of the present invention, there is provided a polishing apparatus for polishing a substrate, comprising: a polishing table having an abrasive surface, and a substrate holding device configured to fix the substrate and the substrate Pressed against the abrasive surface. The substrate holding device comprises an elastic film configured to form a substrate holding surface to be in contact with the substrate, a carrier disposed above the elastic film, and at least one pressure chamber formed on the elastic film and the carrier A first passage between and with the pressure chamber, wherein only a dew-point temperature gas at a pressure of not more than 20 ° C at atmospheric pressure is supplied into the pressure chamber.

According to the present invention, when the pressure of the pressure chamber is increased from the vacuum state to the atmospheric pressure, even if the elastic film is cooled by deionized water (pure water) for cleaning the top ring or the like, only the dew point temperature is Gas that does not exceed 20 ° C at atmospheric pressure is supplied to the pressure chamber. The job is that there is no elastic film condensation in the pressure chamber.

According to the present invention, the temperature of a substrate such as a semiconductor wafer can be controlled by estimating the temperature of the substrate. More specifically, the present invention has the following effects:

(1) When the temperature of the substrate increases during the grinding, the rigidity of the polishing pad is lowered, so that the polishing flatness is lowered. This is because the concave portion of the surface of the substrate pattern is roughened due to the decrease in the rigidity of the polishing pad, and therefore the step height removal cannot be achieved. According to the present invention, the substrate temperature can be estimated with high accuracy, and if the substrate temperature reaches a predetermined value or higher, factors such as grinding conditions are changed, thereby suppressing an increase in the substrate temperature.

(2) The reaction temperature is a very important parameter due to the chemical change of the surface of the substrate caused by the slurry. According to the present invention, since the substrate temperature can be estimated with high accuracy, the substrate can be ground in a temperature range suitable for the properties of the slurry in various processes. For example, in a process in which the polishing rate is lowered at a predetermined value or a higher grinding temperature, the substrate temperature can be estimated with high accuracy, and the grinding conditions are changed so that the grinding temperature is not increased to a predetermined or higher temperature. In comparison, the polishing conditions are changed at a polishing rate of a predetermined value or lower, so that the substrate temperature is not lowered to the predetermined or lower temperature. In addition, when defects in foreign matter or scratches on the substrate occur during the process, the execution of the step removal, the polishing stability, and the like are determined depending on the polishing temperature rather than the polishing rate, and the polishing temperature will take into account the substrate. Control is performed by the effects of the above defects, the execution of the step removal, and the polishing stability.

(3) According to the present invention, since the substrate temperature can be estimated with high accuracy, the temperature distribution in the surface of the substrate can be grasped with high accuracy. Then, by controlling the temperature distribution in the surface of the substrate to be uniform, the polishing characteristics in the surface of the substrate can be uniformly controlled, or the temperature in the surface of the substrate can be controlled to a desired temperature distribution. For example, in the case where the film thickness distribution of the substrate before polishing is uneven, in order to make the film thickness of the substrate uniform after polishing, the temperature distribution in the substrate can be controlled by the temperature of the substrate during the polishing so as to intentionally generate the substrate. Temperature distribution.

Further, according to the present invention, since the temperature estimation of the film (elastic film) and the temperature estimation of the substrate can be performed, the following effects can be obtained.

(1) By estimating the temperature of the film, the above-mentioned substrate temperature estimation effect can be indirectly obtained.

(2) The film thermally expands by temperature. Since the fixing ring is located on the outer peripheral side of the film, if the thermal expansion of the film is expanded, the peripheral side of the film is in contact with the inner peripheral side of the fixing ring, thereby confining the outer peripheral side of the film. Then, the film forms wrinkles or the film is deformed, thereby hindering the film from being pressed against the substrate. According to the present invention, since the film temperature is graspable, the amount of thermal expansion of the film can be controlled, and the film temperature is controlled so that the film does not come into contact with the fixing ring.

(3) When the temperature of the film is increased, the hardness of the film is lowered (the film becomes soft), and thus the pressure applied to the outer peripheral portion of the substrate is changed in particular. Under normal conditions, the substrate is pressed against by inflating the outer peripheral portion of the film. When the hardness of the film is lowered, the rubber tension required to inflate the film is lowered, and the air bag (pressure applied to the film) is reduced in pressure due to rubber tension. As a result, the pressure applied to the substrate exceeds expectations. According to the present creation, since the film temperature can be grasped and controlled, the hardness of the film can be maintained within a certain range, so that the pressing force applied to the substrate is maintained at a desired constant value. Further, based on the temperature of the film, the pressure of the air bag can be controlled so that the pressing force applied to the substrate is kept constant. Specifically, as the film temperature increases, the film becomes soft and the pressure of the air bag is reduced.

Further, according to the present invention, when the pressure of the pressure chamber is increased from the vacuum state to the atmospheric pressure state, the air in the atmosphere at which the grinder is placed can be supplied to the pressure chamber from a gas source isolated from the atmosphere. Therefore, air containing moisture can be prevented from entering the pressure chamber, and the elastic film in the pressure chamber can also be prevented from dew condensation.

BRIEF DESCRIPTION OF THE DRAWINGS A grinding apparatus according to an embodiment of the present invention will be described with reference to Figs. 1 through 22, and similar or corresponding components will be designated by similar or corresponding part numbers in the drawings without repeating the description. .

1 is a schematic view showing the overall structure of a polishing apparatus according to an embodiment of the present invention. As shown in FIG. 1, the polishing apparatus includes a polishing table 100 and a top ring 1 for holding an object to be polished, for example. A substrate of a semiconductor wafer is pressed against the abrasive surface of the polishing table 100.

The polishing table 100 is coupled to a motor (not shown) disposed under the polishing table 100 by a table shaft 100a. Therefore, the polishing table 100 is rotated about the table axis 100a. The polishing pad 101 is attached to the upper surface of the polishing table 100, and the upper surface 101a of the polishing pad 101 constitutes an abrasive surface to polish the semiconductor wafer W. The polishing liquid supply nozzle 102 is disposed above the polishing table 100, and supplies a polishing liquid (polishing slurry) Q to the polishing pad 101 on the polishing table 100.

Various types of polishing pads are commercially available, such as SUBA800, IC-1000, and IC-1000/SUBA400 (two-layer cloth) manufactured by Nitta-Haas Inc., and Surfin xxx manufactured by Fujimi Inc. -5 and Surfin 000, while Surfin 000 is made of non-woven fabrics bonded by urethane resin, while IC-1000 is made of rigid foamed polyurethane (single layer) . The foamed polyurethane is porous and forms a large number of fine cavities or holes on its surface.

The top ring 1 basically includes a top ring body 2 for pressing the semiconductor wafer W against the polishing surface 101a, and the fixing ring 3 can hold the peripheral edge of the semiconductor wafer W to avoid the semiconductor wafer W. Slide out the top ring 1.

The top ring 1 is coupled to the top ring shaft 111, and the top ring shaft 111 is vertically moved along the top ring head 110 by a vertical moving mechanism 124. When the top ring shaft 111 moves vertically, the top ring 1 is raised or lowered as a whole to be positioned along the top ring head 110. A rotary joint 25 is mounted to the upper end of the top ring head 110. The vertical movement mechanism 124 vertically moves the top ring shaft 111 and the top ring 1 , and has a bridge 128 supporting the top ring shaft 111 such that the top ring shaft 111 can be mounted to the bridge portion 128 by bearings 126 . The upper ball screw 132 is supported by a support stage 129 supported by the plurality of rods 130 and an AC servo motor 138 provided on the support plate 129. The support plate 129 supports the AC servo motor 138 and is fixed to the top ring head 110 by a plurality of rods 130.

The ball screw 132 has a screw shaft 132a coupled to the AC servo motor 138, and a nut 132b that screws the screw shaft 132a. The top ring shaft 111 is configured to be vertically movable with the bridge portion 128. Therefore, when the AC servo motor 138 is driven, the bridge portion 128 is vertically moved by the ball screw 132. As a result, the top ring shaft 111 and the top ring 1 are vertically moved.

Further, the top ring shaft 111 is coupled to a rotary sleeve 112 by a key (not shown) having a timing pulley 113 fixedly disposed around the rotary sleeve 112. The top ring motor 114 is fixed to the top ring head 110. The synchronous wheel 113 is operatively coupled to a synchronous wheel 116 disposed on the top ring motor 114 by a timing belt 115. Therefore, when the top ring motor 114 is driven, the synchronous wheel 116, the timing belt 115, and the synchronous wheel 113 are rotated to rotate the rotating sleeve 112 in unison with the top ring shaft 111, thereby rotating the Top ring 1. The top ring head 110 is supported on a top ring head shaft 117 which is rotatably supported by a frame (not shown). The polishing apparatus has a controller 50 that controls each of the devices including the top ring motor 114, the AC servo motor 138, the polishing table motor, and the like.

In the polishing apparatus constructed as shown in Fig. 1, the top ring 1 is configured to hold, for example, a semiconductor wafer W on its lower surface. The top ring head 110 pivots about the top ring head shaft 117. Therefore, the top ring 1 holds the wafer W on the lower surface thereof by the pivotal movement of the top ring head 110, and from the top The position at which the ring 1 accommodates the wafer W is moved to a position above the polishing table 100. Thereby, the top ring 1 is lowered to press the semiconductor wafer W against the surface (abrasive surface) 101a of the polishing pad 101. At this time, when the top ring 1 and the polishing table 100 are respectively rotated, the polishing liquid is supplied from the supply nozzle 102 provided above the polishing table 100 to the polishing pad 101. In this manner, the semiconductor wafer W is in sliding contact with the surface 101a of the polishing pad 101. Therefore, the surface of the semiconductor wafer W is ground.

Next, referring to Fig. 2, the top ring (grinding ring) of the polishing apparatus according to the present invention will be described later. Figure 2 is a cross-sectional view showing the top ring 1 constituting the substrate holding device, which holds the semiconductor wafer W as the object to be polished, and presses the semiconductor wafer W against the grinding table. surface. Fig. 2 shows only the main structural elements constituting the top ring 1.

As shown in FIG. 2, the top ring 1 basically includes a top ring body (also referred to as a carrier) 2 for pressing a semiconductor wafer W against the polishing surface 101a, and a fixing ring 3 for The abrasive surface 101a is directly pressed. The top ring body (carrier) 2 is a circular plate configuration, and the fixing ring 3 is attached to a peripheral portion of the top ring body 2. The top ring body 2 is made of, for example, a resin of engineering plastics such as polyetheretherketone (PEEK). As shown in Fig. 2, the top ring 1 has an elastic film 4 attached to the bottom surface of the top ring body 2. The elastic film 4 is in contact with the back surface of the semiconductor wafer held by the top ring 1, and the elastic film 4 is made of a strong and durable rubber material (for example, ethylene propylene rubber (EPDM), urethane rubber (polyurethane rubber). ), made of silicone rubber, or the like. The elastic film 4 constitutes a substrate holding surface for holding a substrate such as a semiconductor wafer.

The elastic film 4 has a plurality of concentric partition walls 4a, and defines a circular central chamber 5 by a partition wall 4a interposed between the upper surface of the elastic film 4 and the lower surface of the top ring body 2. An annular ripple chamber 6, an outer chamber 7, and an annular edge chamber 8. Specifically, the central chamber 5 is defined in a central portion of the top ring body 2, and the corrugated chamber 6, the outer chamber 7, and the edge chamber 8 are concentrically sequentially from the central portion of the top ring body 2. To the surrounding part is defined. The top ring body 2 is formed with a passage 11 communicating with the central chamber 5, a passage 12 communicating with the corrugated chamber 6, a passage 13 communicating with the outer chamber 7, and a passage 14 communicating with the edge chamber 8. A passage 11 communicating with the central chamber 5, a passage 13 communicating with the outer chamber 7, and a passage 14 communicating with the edge chamber 8 are connected to the passage 21, the passage 23, and the passage 24 by a rotary joint 25, respectively. . The passage 21, the passage 23, and the passage 24 are connected to a pressure adjusting unit 30 via the respective valves V1-1, V3-1, and V4-1, and the pressure regulators R1, R3, and R4, respectively. Furthermore, the channel 21, the channel 23, and the channel 24 are connected to a vacuum source 31 via valves V1-2, V3-2, and V4-2, respectively, and via valves V1-3, V3-3, and V4. -3 can communicate with the atmosphere.

In addition, the passage 12 communicating with the corrugated chamber 6 can be connected to the passage 22 by the rotary joint 25, and then the passage 22 passes through the gas-liquid separator 35, the valve V2-1 and the pressure regulator R2, and the pressure adjustment Unit 30 is connected. Further, the passage 22 is connected to the vacuum source 131 via the gas-liquid separator 35 and the valve V2-2, and is communicated with the atmosphere through the valve V2-3.

Further, a fixing ring pressure chamber 9 composed of an elastic film is formed immediately above the fixing ring 3, and the fixing ring pressure chamber 9 is formed in the top ring body 2 (carrier) The passage 15 and the rotary joint 25 are connected to the passage 26. Subsequently, the passage 26 is connected to the pressure regulating unit 30 via a valve V5-1 and a pressure regulator R5. Further, the passage 26 is connected to the vacuum source 31 via the valve V5-2, and is communicable with the atmosphere via the valve V5-3. The pressure regulators R1, R2, R3, R4 and R5 have pressure regulating functions for adjustment from the pressure regulating unit 30 to the central chamber 5, the corrugated chamber, the outer chamber 7, the edge chamber 8, and the retaining ring One of the pressure chambers 9 pressurizes the respective pressures of the fluid. Pressure regulators R1, R2, R3, R4 and R5, and valves V1-1 to V1-3, V2-1 to V2-3, V3-1 to V3-3, V4-1 to V4-3 and V5 -1 to V5-3 are all connected to the controller 50, and the operation of these pressure regulators and valves is controlled by the controller 50. Further, pressure sensors P1, P2, P3, P4, and P5 and flow rate sensors F1, F2, F3, F4, and F5 are provided in the respective channels 21, 22, 23, 24, and 26, respectively.

Further, in the top ring 1 shown in FIG. 2, the center chamber 5 is defined in a central portion of the top ring body 2, and the corrugated chamber 6, the outer chamber 7, and the edge chamber 8 are concentrically arranged. From the central portion of the top ring body 2 to the surrounding portion is defined. The pressures of the fluid supplied to the central chamber 5, the corrugated chamber 6, the outer chamber 7, the edge chamber 8, and the fixed ring pressure chamber 9 are controlled by the pressure adjusting unit 30 and the pressure regulators R1, R2. R3, R4 and R5 are independently controlled. With such a structure, the pressing force of the semiconductor wafer W against the polishing pad 101 can be adjusted in various regions of the semiconductor W, and the polishing pad 101 is pressed by the control ring 3. The pressure can be adjusted.

Next, successive grinding operations of the polishing apparatus as shown in Figs. 1 and 2 will be described later.

The top ring 1 receives and holds the semiconductor wafer W from the substrate transfer device (transfer device) under vacuum. Therefore, the top ring 1 holding the semiconductor wafer W under vacuum is lowered to the front of the top ring, which is previously set. Preset the grinding position. The fixing ring 3 is in contact with the surface (abrasive surface) 101a of the polishing pad 101 at the predetermined polishing position. Before the semiconductor wafer W is polished, the semiconductor wafer W is attracted and held by the top ring 1 between the bottom surface (the surface to be polished) of the semiconductor wafer W and the polishing surface 101a of the polishing pad 101. There is a small gap of about 1 mm (1 mm). At this time, the polishing table 100 and the top ring 1 are rotated about their own axes. In this state, the elastic film 4 located on the upper surface (reverse surface) of the semiconductor wafer W is expanded under the pressure of the input fluid, and is pressed. The surface (the surface to be polished) against the semiconductor wafer W is pressed against the polishing surface 101a of the polishing pad 101. When the polishing table 100 and the top ring 1 are moved relative to each other, the lower surface (the surface to be polished) of the semiconductor wafer W is ground to a predetermined state (for example, a predetermined film thickness). After the ground semiconductor wafer W is completed on the polishing pad 101, the top ring 1 holds the semiconductor wafer W under vacuum, and the top ring 1 is lifted and moved to the substrate transfer device (moving device), and then The ground semiconductor wafer W is removed (released) from the top ring 1.

Figure 3 is a schematic cross-sectional view showing the main structural elements of the top ring 1. As shown in FIG. 3, the top ring 1 basically comprises a top ring body 2 capable of pressing a semiconductor wafer W (substrate) against the polishing pad 101, and a fixing ring directly pressed against the polishing surface 101a. 3. The top ring body 2 includes a top ring flange 41 at the upper portion, a top ring spacer 42 at the intermediate portion, and a carrier 43 at the lower portion.

The elastic film 4 has a plurality of concentric partition walls 4a, and a partition wall 4a between the upper surface of the elastic film 4 and the lower surface of the top ring body 2 defines a circular center chamber 5 and an annular corrugated chamber. 6. An annular outer chamber 7, and an annular edge chamber 8. Specifically, the central chamber 5 is defined in a central portion of the top ring body 2, and the corrugated chamber 6, the outer chamber 7, and the edge chamber 8 are concentrically sequentially from the central portion of the top ring body 2. To the surrounding part is defined. The top ring body 2 is formed with a passage 11 communicating with the central chamber 5, a passage 12 communicating with the corrugated chamber 6, a passage 13 communicating with the outer chamber 7, and a passage 14 communicating with the edge chamber 8. Then, a passage 11 communicating with the central chamber 5, a passage 12 communicating with the corrugated chamber 6, a passage 13 communicating with the outer chamber 7, and a passage 14 communicating with the edge chamber 8 are respectively passed through a rotary joint 25 It is connected to various pressure chamber pressure lines (not shown). Each pressure chamber pressure line is connected to the pressure regulating unit 30 via respective pressure regulators R1, R3, and R4 (see Fig. 2) (see Fig. 2).

Further, a fixed ring pressure chamber 9 composed of an elastic film 32 is formed immediately above the fixed ring 3. The elastic film 32 is housed in a cylinder 33 fixed to one of the top ring flanges 41. The fixed ring pressure chamber 9 is connected to the pressure chamber pressure line (not shown) by a passage 15 formed in the top ring body 2 and the rotary joint 25 (see Fig. 1). Subsequently, the pressure chamber pressure line of the fixed ring pressure chamber 9 is connected to the pressure adjusting unit 30 via a pressure regulator R5 (see Fig. 2) (see Fig. 2).

As shown in FIG. 3, four infrared thermometers 45 are provided on the carrier 43 of the top ring 1, specifically, four infrared thermometers 45 are respectively facing the center chamber 5 and the annular corrugated chamber 6 The annular outer chamber 7 and the annular edge chamber 8 can each measure the temperature of the thin film 4 corresponding to each of the pressure chambers 5, 6, 7, and 8, respectively. Further, a thermocouple 48 is attached to the upper surface of the carrier 43 of the top ring 1, so that the thermocouple 48 can measure the temperature of the carrier 43. Each of the infrared thermometers 45 and the thermocouples 48 are connected to a cold junction temperature sensor unit 46 via wiring.

According to the present invention, the temperature of the film 4 is measured by an infrared thermometer 45, and the temperature of the substrate is estimated by the temperature measured by the film 4. A thermopile element is placed in the infrared thermometer 45. An infrared ray emitted from the film 4 as a measurement target is incident on the thermopile element, and outputs a thermo electromotive force corresponding to the amount of infrared rays incident on the thermopile element. In the present embodiment, a thermoelectromotive force equivalent to the output amount of the K thermocouple is output. This electromotive force is applied to the cold junction temperature sensing unit 46 through the wiring from the infrared thermometer 45. The cold junction temperature sensing unit 46 has a sensor to measure the temperature of the atmosphere. The electromotive force is converted into a temperature corresponding to the K thermocouple in the cold junction temperature sensing unit 46, and the measured cold junction temperature is added to the converted temperature, and the obtained temperature is To measure the temperature. The cold junction temperature sensing unit 46 has an analog-to-digital converter, and converts the measured temperature into a digital signal via the analog-to-digital converter, and then the digit The signal is sent to a data receiving unit 47.

Since the electromotive force from the infrared thermometer 45 is very small, an anti-noise measure such as winding a shielded wire around the wiring is employed. Further, in the case where the thermocouple output is connected by a connector, it is necessary to make the metal material of the connector to be the same as the metal material of the K thermocouple. In this way, the amount of infrared rays emitted from the film 4 is measured, but the measured value differs from the actual film temperature. Since the upper surface of the film 4 has a certain degree of reflectance in many cases, the infrared rays emitted from the carrier 43 of the top ring 1 are reflected from the film 4, and the reflected light is measured by the infrared thermometer 45. Therefore, the infrared thermometer 45 is affected by the infrared rays from the film 4 and the infrared rays from the carrier 43. In order to minimize this effect, surface texturing is applied to the upper surface of the film 4, and the reflection coefficient of the infrared rays is lowered to improve the measurement accuracy. This surface texture is a process of forming minute unevenness on the surface of the film 4. By forming a slight unevenness on the surface of the film 4 so that the upper surface of the film 4 is rough, the reflection coefficient of infrared rays can be lowered. Therefore, the infrared rays emitted from the carrier 43 to the film 4 can be prevented from being reflected from the film 4, so that the infrared thermometer 45 can measure the amount of infrared radiation from the film 4 under test with high accuracy. In this way, the reflection coefficient of the film 4 can be reduced, and the influence of the infrared rays from the carrier 43 can be reduced, and the temperature of the film 4 can be measured by the infrared temperature, and then the temperature of the substrate can be utilized to measure the film temperature. And estimate it.

However, in the case where the surface texture is not applied to the upper surface of the film, the infrared thermometer 45 is affected by the infrared rays from the film 4 and the infrared rays from the carrier 43. The job is to measure the temperature of the carrier 43 by the thermocouple 48, and to measure the value of the infrared thermometer 45 and the measured value of the thermocouple, the temperature of the wafer can be estimated with high accuracy. The temperature measurement of the carrier can be carried out in the same manner as the film by a noncontact-type thermometer or by a contact-type thermocouple. In the case of using a contact type thermocouple, a thermocouple is connected to the cold junction temperature sensing unit 46 (as measured by the infrared thermometer 45), and the measured temperature is delivered to the data receiving unit. 47.

Next, a method for calculating the wafer temperature estimation value by using the infrared temperature measurement value and the carrier temperature measurement value will be described. Figure 4 is a cross-sectional view showing an experimental apparatus for measuring the temperature of the wafer, the temperature of the film, the temperature of the carrier, and the like when a semiconductor wafer (substrate) is heated and cooled. As shown in FIG. 4, an infrared thermometer 45 is disposed on the carrier 43 of the top ring 1, a thermocouple 48 is attached to the upper surface of the carrier 43, and a thermocouple 49 is attached to the film 4. On the upper surface, a thermocouple 51 is attached to the lower surface of the semiconductor wafer W. In addition, a wafer heating and cooling device 52 is provided for heating and cooling the semiconductor wafer W.

The lower surface of the semiconductor wafer W is heated by forced heating, and then cooled by forced cooling using the experimental apparatus shown in FIG. 4, and the temperature measurement of the lower surface of the thermocouple wafer is obtained, and the thermocouple film is obtained. Surface temperature measurement, infrared temperature measurement, and vehicle temperature measurement. Specifically, the temperature of the lower surface of the wafer is measured by the thermocouple 51, the temperature of the upper surface of the film is measured by the thermocouple 49, the infrared temperature is measured by the infrared thermometer 45, and the temperature of the carrier is measured. Measured by thermocouple 48. In this case, it is considered that the measurement error obtained by the contact type thermocouple is the smallest. In Fig. 4, although the thermometer is only disposed in the central chamber 5 in order to simplify the explanation, the temperature of each of the other pressure chambers, for example, the annular corrugated chamber 6, the annular outer chamber 7, and the like may be simultaneously applied. Measure.

Figure 5 is a diagram showing the surface of the semiconductor wafer (substrate) W, which is heated by forced heating by using the experimental apparatus shown in Fig. 4, and then cooled by forced cooling. A plot of the time variation of this temperature. As shown in Fig. 5, since the lower surface side of the semiconductor wafer is heated by forced heating, the temperature rise of the semiconductor wafer is the fastest, and then the temperature of the upper surface of the film rises, and the temperature of the carrier rises the slowest. Therefore, in the case where the lower surface side of the semiconductor wafer is transferred to forced cooling, the temperature of the semiconductor wafer drops the fastest, and then the temperature of the upper surface of the film drops, and the temperature of the carrier drops the slowest. The infrared temperature measurement value and the film upper surface measurement value showed almost the same tendency during heating and during cooling.

Figures 6A and 6B are graphs drawn using all of the time-series data shown in Figure 5, where the infrared temperature measurements are plotted on a horizontal axis and simultaneously measured by a thermocouple. The film upper surface temperature measurement is plotted on the vertical axis. Fig. 6A shows the pressure chamber measurement results without the surface texture on the upper surface of the film, and Fig. 6B shows the pressure chamber measurement results on the upper surface of the film having the surface texture (applying surface roughening). As shown in FIG. 6A, in the case where the upper surface of the film does not have a surface texture, some errors occur during heating and during cooling, which are between the infrared temperature measurement value and the upper surface temperature measurement value of the thermocouple film, and thus The resulting results show gentle curves. As shown in Fig. 6B, in the case where the upper surface of the film has a surface texture, some errors occur during the heating and during the cooling period between the infrared temperature measurement value and the upper surface temperature measurement value of the thermocouple film, thus The result is a soft curve. However, in Fig. 6B, since the degree of error is small, the result drawn is close to a straight line. In this way, in the case of a pressure chamber without a surface texture and a pressure chamber having a surface texture, some errors occur between the temperature measurement value of the infrared thermometer film and the temperature measurement value of the thermocouple film, and thus the error effect has been Removed by linear approximation. in particular,

Thermocouple output value (film temperature estimate) = coefficient a × infrared temperature measurement value + coefficient b‧‧‧(1)

By finding the coefficient a and the coefficient b that satisfy the relationship of equation (1), the film temperature can be estimated by simple linear regression analysis. In the following, the estimated film temperature estimate by the simple linear regression equation is referred to as the correction value of the infrared radiation thermometer measurement.

In Figures 7A and 7B, the infrared temperature measurement correction values in the respective graphs are plotted on the horizontal axis, while the film upper surface temperature measurement values measured by the thermocouple are plotted on the vertical axis. Specifically, the graphs in FIGS. 7A and 7B show the relationship between the corrected value of the infrared temperature measurement value and the measured value of the thermocouple after the linear approximation. Fig. 7A shows the result of the area where the upper surface of the film does not have a surface texture, and Fig. 7B shows the result of the area having the surface texture on the upper surface of the film.

Fig. 7A shows that during the forced heating, the correction value of the film temperature measurement measured by the infrared thermometer is lower than the film temperature measurement measured by the actual thermocouple. Specifically, since the temperature rise of the carrier is delayed during the forced heating, the infrared rays irradiated from the low temperature carrier are reflected on the film, and the reflected infrared rays are incident on the infrared thermometer. The job is to measure the correction value below the actual film temperature. In comparison, during the forced cooling, the correction value of the film temperature measurement measured by the infrared thermometer is higher than the film temperature measurement measured by the actual thermocouple. Specifically, since the temperature drop of the carrier is delayed during the forced cooling, the infrared rays irradiated from the high temperature carrier are reflected from the film, and the reflected infrared rays are incident on the infrared thermometer. Therefore, the measurement correction value is higher than the actual film temperature.

In Fig. 7B, since the surface texture is applied to the upper surface of the film, the infrared rays emitted from the carrier are diffused and reflected from the upper surface of the film, and thus the reflected infrared rays have less influence on the measured value of the infrared thermometer. It is assumed that during the forced heating and forced cooling, the film temperature actually measured by the thermocouple and the film temperature correction measured by the infrared temperature are generally consistent with each other. Therefore, it can be confirmed that on the upper surface of the film to which the surface texture is applied, the film temperature can be estimated with a relatively high accuracy by an infrared thermometer.

As described above, Figures 7A and 7B show that, especially when the surface texture is not applied to the upper surface of the film, when the infrared rays from the carrier are reflected from the upper surface of the film, the infrared temperature measurement value is relatively large. At the time of influence, the film temperature cannot be estimated with high accuracy from the correction value measured by the infrared thermometer. In this way, since the measured value of the infrared thermometer is affected by the temperature of the carrier, the estimated temperature of the film is calculated by multiple linear regression analysis using the infrared temperature measurement correction value and the vehicle temperature measurement value. By. In this multiple linear regression analysis, the regression coefficients b ₀ , b ₁ and b _{2 of the} minimization (the temperature measurement of the thermocouple measurement - the film temperature estimate) ^{2 are} calculated. Specifically, multiple linear regression analysis using method of least squares is employed.

(Thin film temperature estimation value) = b ₀ + b ₁ × (infrared temperature measurement correction value) + b ₂ × (vehicle temperature measurement value) ‧ ‧ equation (2)

In the graphs of Fig. 8A and Fig. 8B, the regression coefficient (regression coefficients) of the multiple linear regression analysis represented by equation (2) in minimization (measurement of film temperature measurement of thermocouple measurement - film temperature estimation) ² ) b ₀ , b ₁ and b ₂ , the actual temperature measurement is used to calculate the film temperature estimation value is plotted on the horizontal axis, while the film upper surface temperature measurement measured by the thermocouple It is drawn on the vertical axis. Fig. 8A shows a case where the upper surface of the film does not have a surface texture, and Fig. 8B shows a case where the upper surface of the film has a surface texture.

As shown in Figures 8A and 8B, in the case of using multiple linear regression to estimate the film temperature, the film estimate can be extremely accurately consistent with the actual film score measurements measured by the thermocouple. By storing the calculated multiple regression coefficients in the grinding device in advance, the film temperature can be estimated with high accuracy in the grinding process. Further, Fig. 8B shows the results of calculations in the case where the respective estimated values were subjected to multiple linear regression analysis using the data shown in Fig. 7B in which the surface texture was applied to the upper surface of the film. The estimated value in the case of Fig. 8B can be consistent with the actual measured value of the film temperature measured by the thermocouple with higher accuracy than the case shown in Fig. 7B. Specifically, multiple linear regression analysis that takes into account the temperature of the carrier is also effective in areas where surface texture is applied.

Figure 9 is a graph showing the results, in which the film temperature is estimated from the multiple linear regression equation from the infrared temperature measurement shown in Figure 5 and the vehicle temperature measurement. In Fig. 9, the measurement system is executed in an area where there is no surface texture. It has been confirmed from Fig. 9 that although the infrared temperature measurement correction value at some positions (the correction value obtained by the linear approximation (simple linear regression analysis) of the case of Fig. 7A) is different from the film temperature measured by the thermocouple. The actual measured value, however, the estimated film temperature obtained by the multiple linear regression equation is consistent with the actual measured temperature of the film temperature measured by the thermocouple.

Next, a method of estimating the wafer temperature (substrate temperature) using the film temperature estimation value will be described below. Figure 10 is a graph drawn using all of the time series data shown in Figure 5, where the film temperature estimates calculated from the film temperature estimation equation are plotted on the horizontal axis while the crystal is measured by the thermocouple. The measurement of the temperature of the lower surface of the circle is plotted on the vertical axis. Figure 10 shows that during forced heating, the film temperature estimate is lower than the actual measured wafer temperature measured by the thermocouple. In comparison, during forced cooling, the film temperature estimate is higher than the actual measured wafer temperature measured by the thermocouple. This phenomenon will be described later.

The film temperature is affected by both the wafer temperature and the carrier temperature from the viewpoint of thermal balance. The film temperature is lower than the wafer temperature during forced heating due to the low temperature carrier. In comparison, the film temperature is higher than the wafer temperature during forced cooling due to the high temperature carrier.

In Figure 10, the film temperature estimate can be determined by simple linear regression analysis of equation (1), and the wafer temperature estimate can be determined by simple linear regression analysis by infrared temperature measurement correction. Also in this case, especially in the case where the surface texture is applied to the upper surface of the film, when the infrared rays incident from the carrier are diffusely reflected from the upper surface of the film, the wafer temperature can be estimated with high accuracy. Some estimates of wafer temperature can be achieved by simple linear regression analysis using film temperature estimates. In order to estimate the wafer temperature with high accuracy, the film temperature can be calculated by the multiple linear regression equation using the film temperature and the carrier temperature, and the estimated value can be calculated with high accuracy. Moreover, in this multiple linear regression analysis, the regression coefficients b ₀ , b ₁ and b _{2 of the} minimization (the wafer temperature measurement of the thermocouple measurement - the wafer temperature estimation value) ² are calculated. Specifically, multiple linear regression analysis using the least squares method is employed.

(wafer temperature estimate) = b ₀ + b ₁ × (film temperature estimate) + b ₂ × (vehicle temperature measurement) ‧ ‧ equation (3)

Figure 11 is a graph in which the regression coefficient b ₀ , b is calculated by applying the actual measurement value to the minimum of the equation (3) (the wafer temperature measurement value of the thermocouple measurement - the wafer temperature estimation value) ² _In the case of ₁ and b ₂ , the wafer temperature measurement is plotted on the horizontal axis, while the wafer lower surface temperature measurement measured by the thermocouple is plotted on the vertical axis. In the case of using the multiple linear regression equation (3) to estimate the wafer temperature, the wafer temperature estimate is extremely accurately consistent with the actual measured value of the lower surface temperature of the thermocouple measurement wafer.

Figure 12 is a graph showing the results, in which the wafer temperature is estimated from the infrared temperature measurement measured in Figure 5 and the measured temperature of the vehicle using a multiple linear regression equation. It is determined that the estimated wafer temperature obtained by using the multiple linear regression equation is extremely accurately consistent with the actual measured value of the lower surface temperature of the thermocouple measurement wafer. By storing the calculated multiple regression coefficients in the grinding device in advance, the wafer temperature can be estimated with high accuracy in the grinding process. In the initial experiment to determine the multiple regression coefficients as shown in Fig. 4, the pressure chamber should be pressurized with the pressure of the actual grinding operation. Furthermore, in the case of actual grinding (actually performing the grinding operation) under certain pressure conditions, the multiple regression coefficients can be calculated in advance under each pressure condition, and can be selectively utilized according to the pressure conditions during the actual grinding. Multiple regression coefficients. In this embodiment, a multiple linear regression analysis of the combined carrier temperature (as the temperature of the substrate holding device (top ring)) is performed. In order to calculate the temperature estimate with high accuracy, the temperature of the part of the carrier facing the film should be used. However, the temperature of the other parts (components) of the device may be held by the substrate without using the temperature of the carrier. In this case, if the temperature of the component connected to the carrier is used, the temperature estimate can be calculated with higher accuracy.

Figure 13 is a view showing the wafer temperature (substrate temperature) estimated from the infrared temperature measurement value and the carrier temperature measurement value in accordance with one aspect of the polishing apparatus of the present invention for determining the polishing conditions, etc. A flow chart of the process of processing conditions.

As shown in Fig. 13, the data acquisition and calculation of the estimation equation are carried out in advance. Specifically, as shown in Fig. 4, the temperature of the lower surface of the wafer is measured by the thermocouple 51, and the upper surface temperature of the film is as measured. Measured by thermocouple 49, the infrared temperature is measured by infrared thermometer 45, and the temperature of the carrier is measured by thermocouple 48. Again, the estimated equations are calculated using these measured values. In this case, the estimation equations of the plurality of pressure chambers are equally calculated as needed. The infrared temperature measurement value is compared with the measured value obtained by the non-contact type thermocouple, and the slope of the infrared temperature measurement value is corrected, and the infrared temperature measurement value and the measurement value obtained by the non-contact type thermocouple are used. The error. Then, the film temperature estimation equation is calculated from a multiple linear regression analysis using the infrared temperature measurement correction value and the vehicle temperature measurement value. The wafer temperature estimation equation is then calculated from a multiple linear regression analysis using film temperature estimates and vehicle temperature measurements. The calculated wafer temperature estimation equation is then stored in the grinding apparatus.

During the actual grinding, the infrared temperature measurement value and the carrier temperature measurement value during the grinding are replaced with the above wafer temperature estimation equation, and the wafer temperature estimation value is calculated. If necessary, the wafer temperature estimate calculated during the grinding can be utilized to change the grinding conditions.

Next, the problem of film condensation explained in the above "Summary of the Invention" will be described later. Film condensation can reduce the accuracy of temperature measurements or make the pressure supplied to the wafer unstable.

Figure 14A is an enlarged view of the XIV portion of Fig. 2, as shown in Fig. 14A, the valve V1-3 can communicate with the atmosphere, and the passage (e.g., the central chamber) that communicates with the pressure chamber is switched from the vacuum state to the pressure relief. At the atmospheric pressure state, air in the atmosphere in which the grinding device is placed enters the valve V1-3, and the pressure chamber is exposed to atmospheric pressure. At this time, the moisture-containing air enters the pressure chamber, and dew condensation occurs on the film due to repeated temperature rise and temperature drop in the pressure chamber. Similarly, the same applies to the valve V2-3 and the like corresponding to the other pressure chambers (for example, the corrugated chamber 6). When dew condensation occurs in the film of the pressure chamber and water droplets are generated on the surface of the film, the amount of infrared radiation emitted from the portion having the amount of water droplets and the portion having no water droplets is changed. At the job, the film temperature cannot be accurately measured. Further, when the number of water droplets caused by condensation increases, the amount of water accumulated in the pressure chamber changes the pressure applied to the wafer, and thus the polishing operation cannot be performed stably.

In order to prevent the moisture-containing air from entering the pressure chamber, when the pressure of the pressure chamber is increased from the vacuum state to the atmospheric pressure state, the nitrogen pressure N ₂ (dry gas) of the atmospheric pressure is supplied. Dry air other than nitrogen but not containing moisture can also be used. In this case, dry air refers to a gas source whose dew-point temperature does not exceed 20 ° C under atmospheric pressure. Usually, the temperature of the deionized water (pure water) used to clean the top ring is about 20 ° C, and if the gas having a dew point temperature of not more than 20 ° C is used, the condensation does not occur even if the gas is cooled to about 20 ° C. The dry air is preferably an inert gas.

Figure 14B is a view showing a piping system for supplying nitrogen gas having atmospheric pressure to the pressure chamber. As shown in Fig. 14B, the valve V1-3 is connected to a pressurization via a regulator or pressure controller 55. Nitrogen source 56. The regulator or pressure controller 55 decompresses the nitrogen supplied to the pressurized nitrogen source 56. In this manner, in order to supply atmospheric pressure nitrogen to the pressure chamber, the pressurized nitrogen gas can be decompressed by the regulator (decompression valve) or pressure controller. In comparison, when the pressure chamber is decompressed from the pressurized state to the atmospheric pressure state, the valve V1-3 communicating with the pressure chamber is opened, and the pressurized gas is discharged from the pressure relief valve of the regulator. And decompressed. Therefore, air containing moisture is prevented from entering the passage. In addition, a container may be provided for storing atmospheric pressure nitrogen gas, and the atmospheric pressure nitrogen gas may be supplied from the vessel to the pressure chamber to increase the responsiveness to changes in atmospheric pressure. According to the invention, the passage in communication with the pressure chamber is only connected to a source of gas that is isolated from the atmosphere in which the grinding device is placed. Specifically, since the passage communicating with the pressure chamber is constructed so as not to be connected to the atmosphere in which the grinding device is placed, the moisture-containing air does not enter the pressure chamber, and condensation is prevented from occurring in the pressure chamber.

Moreover, in the aspect in which the dry gas source as shown in FIG. 2 is not provided, a water content removing device may be disposed in each channel that communicates with the pressure chamber and is equipped with an infrared thermometer (at In the channels 21, 22, 23 and 24 or the channels 11, 12, 13 and 14) in the embodiment 2, it is thus possible to supply a gas having a dew point temperature not exceeding 20 ° C to each pressure chamber. In the case of the moisture removing device, a water-absorbent material such as silica gel or water absorptive polymer is provided in the passage, and the water-absorbent material is replaced at the same time as the replacement film or the like. In other respects, in order to prevent condensation from occurring on the pressure chamber side, it is considered that the film itself is manufactured by using a high heat insulating film or using warm water to wash the top ring, thereby avoiding a decrease in film temperature.

Next, the data receiving unit 47 shown in Fig. 3 will be described later. As shown in Fig. 3, the data receiving unit 47 is mounted in the top ring 1 which is scrolled during the grinding process, and therefore it is necessary to transmit a signal between the rolling portion and the stationary portion as a controller of the grinding device. Signal transmission with the data receiving unit 47. For this signal transmission, a slip ring, or radio communication such as radio wave communication, or optical communication (not shown) may be used. According to this embodiment, the signal measured by the infrared thermometer 45 or the thermocouple 48 is measured by the analog-to-digital converter, and the measured temperature is analogized by the cold junction temperature sensing unit 46-to- The digital converter converts into a digital signal, which is then sent to a data receiving unit 47. Then, the digital signals are transmitted from the data receiving unit 47 to the controller 50 of the polishing apparatus (refer to FIG. 1), and therefore the system is not affected by the noise generated by the slip ring or the radio communication. The slip ring can be used to supply power to the data receiving unit 47, or to use a coil or the like as a non-contact power supply to the data receiving unit 47. In addition, a rechargeable battery can be disposed in the top ring 1 to provide power. In this case, the remaining battery power can be recognized by the controller 50 of the grinding device, and when the remaining battery power is low, a warning sound can be issued from the grinder to remind the battery replacement person.

Next, a method of controlling the temperature of the pressure chamber will be described. Figure 15 is a schematic cross-sectional view of the top ring having a structure for performing temperature control of the pressure chamber. In Fig. 15, the infrared thermometer and some of the elements described in Fig. 3 are omitted. As shown in Fig. 15, the first pressure controller 60-1 and the second pressure controller 60-2 are coupled to a pressure chamber (e.g., the center chamber 5), and a pressure sensor 61 is provided to monitor the pressure chamber ( The pressure inside the central chamber 5). The first pressure controller 60-1 and the second pressure controller 60-2 are set at the same control pressure at the start of the grinding. When the wafer temperature estimate exceeds a predetermined temperature during the polishing process, the predetermined value of one of the first pressure controller 60-1 and a second pressure controller 60-2 is lowered. For example, at the beginning of the grinding, both the first pressure controller 60-1 and the second pressure controller 60-2 pressurize a fluid to a set value of 200 hPa, and pressurize the wafer during pressurization to 200 hPa. When the wafer temperature estimate exceeds the predetermined temperature, the set pressure of the second pressure controller 60-2 is lowered to 180 hPa, and the set pressure of the first pressure controller 60-1 is maintained at 200 hPa. In this case, the pressurized fluid flows from the fluid passage in communication with the first pressure controller 60-1 toward the fluid passage in communication with the second pressure controller 60-2. The flow of this pressurized fluid cools the internal temperature of the pressure chamber (central chamber 5). In addition, the pressure of the pressure chamber during cooling is monitored by the pressure sensor 61, and when the pressure in the pressure chamber drops far below 200 hPa, the set pressure of the second pressure controller 60-2 increases, thus The required pressure is created in the pressure chamber.

In order to further improve the cooling effect in the pressure chamber, it is preferable to further reduce the set pressure of the second pressure controller 60-2 to increase the flow rate of the pressurized fluid flowing through the pressure chamber. The pressurized fluid can have a controlled temperature, for example, a pressurized fluid having a low temperature can be used to further improve the cooling effect. Alternatively, a pressurized fluid having a high temperature may be used. For example, when the wafer temperature estimate is not more than the predetermined temperature, the high temperature pressurized fluid may flow through the pressure chamber, thereby increasing the temperature of the wafer. A combination of a low temperature pressurized fluid and a high temperature pressurized fluid may also be used, for example, when the wafer temperature is at a low temperature in the initial stage of the grinding, the high temperature pressurized fluid flows through the pressure chamber, thereby accelerating the increase in the wafer temperature. When the wafer temperature becomes higher during the grinding, the pressurized fluid having a low temperature or a normal temperature is caused to flow through the pressure chamber, thereby suppressing an increase in the wafer temperature. The film that is pressed against the wafer can be configured to define a plurality of pressure chambers and the wafer temperature is estimated and controlled in each pressure chamber. In addition, the wafer temperature can be estimated in one of the pressure chambers, and the temperature is controlled using this estimated temperature. Moreover, since the pressure sensor 61 has a temperature characteristic, the measured value of the pressure sensor 61 can be compensated by the temperature measurement result of the carrier 43.

The wafer temperature estimate is further used to vary various polishing conditions when the wafer temperature estimate corresponding to a portion of a pressure chamber (eg, the central chamber 5) during polishing is higher than corresponding to another pressure chamber (eg, the ripple Comparing the wafer temperature estimate of part 6), the pressure of the one pressure chamber (central chamber 5) is lowered, thereby suppressing the temperature rise; or the pressure of the other pressure chamber (corrugation chamber 6) is increased, Thus, the temperature rise in the other pressure chamber (corrugation chamber 6) is accelerated. Furthermore, the cooling and heating means (provided outside the substrate holding means) of the grinding surface 101a can be used to control the temperature of the entire grinding surface 101a, or can be used to control the grinding surface 101a corresponding to the pressure chamber portion of the measured temperature. The temperature. Examples of temperature control devices for controlling the abrasive surface include those configured to contact a media with the abrasive surface to control its temperature, and a device configured to blow a fluid onto the abrasive surface. In order to control the grinding temperature, the pressing force of the control ring (refer to Fig. 1) can be changed, or the wearing conditions (such as the dressing load and the scanning speed) can be measured on the grinding surface corresponding to the temperature. Portions of the pressure chamber can be modified to accelerate or inhibit the grinding process. Renovation can be changed when performing in-situ dressing (ie, finishing work performed during grinding) or performing ex-situ dressing (ie, finishing work performed after grinding) condition. The flow rate of the slurry can be changed for temperature control, and the temperature measurement result can change the falling position of the slurry, and a combination of these temperature control devices can also be used. In addition, the temperature of the polishing surface can also be measured, and the temperature measurement result of the polishing surface and the temperature measurement result of the wafer can be utilized to perform the above temperature control.

Next, specific examples of the temperature control device for the above-mentioned polishing surface will be described with reference to Figs. 16 to 21 .

Figure 16 is a plan view showing a configuration of a slurry supply nozzle for supplying a slurry (grinding liquid), the polishing pad, and the top ring. As shown in Fig. 16, the polishing liquid supply nozzle 102 is disposed above the polishing table 100, so that the polishing liquid supply nozzle 102 causes the polishing slurry to fall (or be supplied) to the polishing pad 101 on the polishing table 100. Location. The tip end of the nozzle portion of the slurry supply nozzle 102 is adjacent to the top ring 1.

Figure 17 is a plan view showing an example of the temperature control device of the polishing pad. In the example shown in Figure 17, when the wafer temperature is high, the polishing pad temperature control device 70 is cooled by the cooling medium. The polishing pad 101 is in contact, thereby cooling the polishing pad 101 (i.e., the cooling surface).

Figure 18 is a plan view showing an example of another temperature control device for the polishing pad. In the example shown in Fig. 18, the polishing pad temperature control device 70 strongly cools the polishing pad 101 at a high temperature portion (e.g., a central portion of the wafer) corresponding to the wafer. Specifically, the intense cooling is performed by the central portion of the polishing pad temperature control device 70 to cool the portion of the polishing pad 101 corresponding to the central portion of the wafer. At the same time, the weaker cooling is also performed by the two sides of the polishing pad temperature control device 70 to cool the portion of the polishing pad 101 corresponding to other portions of the wafer that would otherwise be heated if the portion is not cooled.

Figure 19 is a plan view showing an example of a dress load and/or a change in the scan speed. As shown in Fig. 19, a dish-shaped dresser 80 is provided for refurbishing the polishing pad 101 on the polishing table 100. During the refurbishment, the dresser 80 is pressed onto the polishing pad 101 by a predetermined finishing load. Furthermore, the dresser 80 can be swung by a horizontally extending swing axis 81 within a scan range of a dresser. When the temperature of the central portion of the wafer is high (or low), the repairing load of the polishing pad corresponding to the portion of the high temperature portion (or low temperature portion) of the wafer is reduced (or increased), thereby adjusting the polishing performance of the polishing pad. When the temperature of the central portion of the wafer is high (or low), the scanning speed of the polishing pad corresponding to the portion of the high temperature portion (or low temperature portion) of the wafer is reduced (or increased), thereby adjusting the polishing performance of the polishing pad. The refurbishment conditions may be changed during the in-situ refurbishment of the refurbishment process performed during grinding, or the refurbishment conditions may be changed when the retreading of the refurbishment process is performed after grinding.

Figure 20 is a plan view showing an example of changing the position at which the slurry falls depending on the temperature of the wafer. As shown in Fig. 20, when the temperature at the central portion of the wafer is high, the angle of the slurry supply nozzle 102 is changed, so that the falling position of the slurry is on the trajectory (Lc) drawn on the polishing pad.

Figure 21 is a plan view showing an example of the temperature (distribution) measurement of the polishing pad simultaneously with the wafer temperature measurement, and the temperature control is performed based on the measured results. In the example shown in Fig. 21, a plurality of infrared thermometers 82 are disposed above the polishing table 100, and the positions of the infrared thermometers 82 are located on the polishing table 100 away from the polishing pad 101. The polishing surface temperature of the polishing pad 101 is measured by the plurality of infrared thermometers 82, and thus the temperature distribution of the polishing surface is measured. Subsequently, the temperature control of the wafer is performed using the estimation result of the wafer temperature and the measurement result of the polishing surface temperature.

In addition to the implementations shown in Figures 16 through 21, an estimate of the wafer temperature (i.e., an estimate of the substrate temperature) can be utilized and embedded in the polishing table and configured to measure the wafer polishing. The combination of the information obtained by the surface sensor (eg, optical or eddy current type) to change the grinding conditions. For example, when the film thickness monitored by the eddy current sensor during the polishing changes slowly over other regions, and when the temperature estimation value of the central portion of the wafer is high, the temperature control device is controlled. Thus, the temperature at the center of the wafer is lowered, which is a suppression when the temperature rises above a certain value during the grinding process. Various forms of control methods can be combined depending on the circumstances of the process. Preferably, the wafer contact surface of the film defining the pressure chamber for measuring the temperature of the film has no openings (e.g., holes). This is because the hole allows the cleaning liquid to enter the upper surface side of the film during the cleaning operation of the substrate holding device, thereby reducing the accuracy of the film temperature measurement. However, in the case where an opening (for example, a hole) is provided, it is preferable to remove a gas (for example, nitrogen) from the side of the carrier to the film temperature measuring area during the cleaning operation of the substrate holding device. Water droplets.

In the case of using a substrate holding device having a plurality of pressure chambers, a plurality of temperature sensors (for example, infrared thermometers) capable of measuring the temperature of the film are provided, and each of the pressure chambers is provided with a measurement. The device can therefore estimate the wafer temperature corresponding to the position of each pressure chamber by a multiple linear regression equation for each film temperature sensor. If not all pressure chambers are provided with pressure sensors, at least two membrane temperature sensors must be provided. In this case, the measurement results of the at least two sensors can be used to perform interpolation calculation and estimate the temperature of the wafer corresponding to the positions of the pressure chambers not provided with the film temperature sensor. The linear temperature interpolation or other interpolation method (for example, quadratic) can be used to estimate the wafer temperature from the measurement results of the two film temperature sensors. According to this method, a smaller number of film temperature sensors can be used to estimate the temperature distribution across the wafer surface. Furthermore, the grinding conditions can be varied using temperature estimates of pressure chambers that are not provided with a film temperature sensor. For example, when the estimated temperature of the pressure chamber is high, the pressure of the pressure chamber is low.

Figure 22 is a cross-sectional view showing a more detailed structure of the top ring having the infrared thermometer and the thermocouple capable of measuring the temperature of the carrier.

The top ring 1 shown in Fig. 22 corresponds to the top ring 1 shown in Fig. 3, but the structure is more detailed. As shown in Fig. 22, the top ring 1 is basically constituted by a top ring body 2 which is configured to press the semiconductor wafer against the polishing surface 101a (refer to Fig. 1). And the retaining ring 3 is configured to directly compress the abrasive surface. The top ring body 2 includes the disc top ring boss 41, a top ring spacer 42 attached to a lower surface of the disc top ring dome 41, and a lower surface of the top ring spacer 42 attached thereto. Carrier 43. The retaining ring 3 is attached to a peripheral portion of the top ring flange 41 of the top ring body 2, and the top ring flange 41 is coupled to the top ring shaft 111 by bolts 308. The top ring spacer 42 is fixed to the top ring flange by bolts (not shown), and the carrier 43 is fixed to the top ring spacer 42 by bolts (not shown). The top ring flange 41, the top ring spacer 42, and the carrier 43 constitute the top ring body (2) made of a resin such as engineering plastic (for example, PEEK). The top ring flange 41 may be made of metal such as stainless steel (SUS) or aluminum.

An elastic film 4 that is in contact with the back surface of the semiconductor wafer is attached to the bottom surface of the carrier 43. More specifically, the film 4 is formed by an annular edge holder 316 disposed at a portion around the film 4 and looper holders 318 and 319 disposed inside the edge holder 316. Attached to the lower surface of the carrier 43. The film 4 is made of a rubber material having excellent strength and durability (for example, ethylene propylene (EPDM), polyurethane rubber, and ruthenium rubber).

The edge holder 316 is held by the corrugated holder 318, and the corrugated holder 318 is attached to the bottom surface of the carrier 43 by a plurality of stoppers 320. Similarly, the corrugated holder 319 is also attached to the bottom surface of the carrier 43 by a plurality of stoppers (not shown). The center chamber 5 is formed at a central portion of the film 4.

The corrugated holder 318 is arranged to press a ripple 314b of the film 4 against the bottom surface of the carrier 34, and the corrugated holder 319 is arranged to press one of the corrugations 314a of the film 4 against the carrier With a bottom surface of 34. One edge 314c of the film 4 is pressed against the edge holder 316 by the corrugated holder 318.

The center chamber 5 is formed at a central portion of the film 4. Further, the annular corrugated chamber 6 is formed between the corrugations 314a of the film 4 and the corrugations 314b. The annular outer chamber 7 is formed by the outer partition wall 314b and the edge partition wall 314c. The annular edge chamber 8 is formed by the edge partition 314c and one of the side walls 314e of the film 4. Each of the pressure chambers 5, 6, 7, and 8 is connected to the pressure adjusting unit 30 (see FIG. 2) through the respective fluid passages formed in the top ring body 2.

The fixing ring 3 is configured to fix the peripheral edge of the semiconductor wafer. The fixing ring 3 includes a cylinder 400 having a closed top and a holding member 402 fixed to the top of the cylinder 400. A film 404 is fixed in the cylinder 400 by the holding member 402, a piston 406 is connected to the bottom end portion of the film 404, and a ring member 408 is pushed down by the piston 406. The fixed ring pressure chamber 9 is formed in the film 404. The film 404 is made of a rubber material having excellent strength and durability such as ethylene propylene rubber (EPDM), urethane rubber, and decane rubber.

The retaining member 402 is provided with a fluid passage (not shown) that communicates with the stationary ring pressure chamber 9 defined by the membrane 404. The fluid passage formed in the holding member 402 is connected to the pressure adjusting unit 30 (see FIG. 2) through a fluid passage formed in the top ring body 2.

In the top ring 1 according to the present embodiment, it is supplied to each pressure chamber formed between the film 4 and the carrier 43 (that is, the center chamber 5, the corrugated chamber 6, the outer chamber 7, and the edge chamber 8) The pressure of each of the fluids, and the pressure of the fluid supplied to the pressure chamber 9 of the stationary ring, can be independently adjusted. According to such a structure, the pressing force of the film 4 for pressing the semiconductor wafer against the polishing pad 101 can be adjusted in each region of the semiconductor wafer, and the fixing ring 3 can be pressed against the polishing pad 101. The pressure is adjusted as needed.

In the embodiment shown in Fig. 22, the infrared thermometer 45 faces the center chamber 5 of the film 4, and the infrared thermometer 45 can be arranged to face the other pressure chamber. In this case, the position of the partition wall of the pressure chamber in the radial direction of the wafer can be appropriately changed. In order to minimize the effects of noise, the infrared thermometer 45 is placed adjacent to the film 4 so as to face the film 4 (i.e., on the side of the carrier). An O-ring 85 can be disposed between the outer surface of the infrared thermometer 45 and the carrier 43, so that the pressurized fluid and the vacuum pressure in the pressure chamber do not leak. A thermocouple 48 for measuring the temperature of the carrier 43 is provided on the upper surface of the carrier 43 at a position corresponding to the center chamber 5. A plurality of thermocouples 48 for measuring the temperature of the carrier 43 may be disposed on the upper surface of the carrier 43, thus corresponding to the respective pressure chambers. The temperature measurement obtained from one of the thermocouples 48 can be used to represent the temperature of the carrier 43 and the temperature of the bottom surface of the carrier 43 can be directly measured. In the case where the temperature of the bottom surface of the carrier 43 is measured by the thermocouple on the upper surface of the carrier 43, it is preferable to make the carrier 34 as thin as possible so that the temperature of the bottom surface of the thermocouple measuring carrier 43 can be obtained. Good responsiveness. In addition, since the carrier 43 is a removable component when replacing the worn top ring, in order to provide an easy-to-remove structure, it is preferable to use a thermocouple connector to connect the infrared thermometer wire to the thermocouple.

In the top ring 1 of the configuration shown in Fig. 22, the infrared thermometer 45 measures the amount of infrared rays from the film 4, and the thermocouple 48 measures the temperature of the carrier 43, as previously referred to Fig. 3. As discussed in FIG. 13, the temperature of the wafer is estimated from the measured value of the infrared thermometer 45 and the measured value of the thermocouple 48.

Although various embodiments of the invention have been described herein, the invention is not limited to the embodiments described above. It is to be understood that the present invention is still applicable to other embodiments within the scope of the technical idea of the present invention.

1. . . Top ring

2. . . Top ring

3. . . M

4. . . Elastic film

4a. . . partition

5. . . Round center room

6. . . Annular corrugated chamber

7. . . Annular outer chamber

8. . . Annular edge chamber

9. . . Fixed ring pressure chamber

13, 14, 15. . . aisle

21, 22, 23, 24. . . aisle

25. . . Rotary joint

26. . . aisle

30. . . Pressure regulating unit

31. . . Vacuum source

35. . . Gas-liquid separator

41. . . Top ring flange

42. . . Top ring divider

43. . . vehicle

45. . . Infrared thermometer

46. . . Cold junction temperature sensing unit

47. . . Data receiving unit

48. . . Thermocouple

49. . . Thermocouple

50. . . Controller

51. . . Thermocouple

52. . . Wafer heating and cooling device

55. . . pressure controller

56. . . Nitrogen source

60-1. . . First pressure controller

61. . . Pressure sensor

62-2. . . Second pressure controller

70. . . Grinding pad temperature control device

80. . . Disk mounter

81. . . Horizontally extending swing axis

82. . . Infrared thermometer

100. . . Grinding table

100a. . . Axle

101. . . Abrasive pad

101a. . . Abrasive pad surface

102. . . nozzle

110. . . Top ring head

111. . . Top ring axle

112. . . Rotating sleeve

113. . . Synchronous wheel

114. . . Top ring motor

115. . . Timing belt

116. . . Synchronous wheel

117. . . Top ring head shaft

124. . . Vertical moving mechanism

126. . . Bearing

128. . . Bridge

129. . . Support stage

130. . . Rod

131. . . Vacuum source

132. . . Ball screw

132a. . . Screw shaft

132b. . . Nut

138. . . AC servo motor

314a, 314b. . . ripple

314c. . . partition

316. . . Edge holder

318. . . Corrugated holder

319. . . Corrugated holder

320. . . Stopper

400. . . Cylinder block

402. . . Holding element

404. . . film

406. . . piston

408. . . Ring

F1, F2, F3, F4, F5. . . Flow rate sensor

P1, P2, P3, P4, P5. . . Pressure sensor

Q. . . Slurry

R1, R2, R3, R4. . . Pressure regulator

V1-1, V1-2, V1-3. . . valve

V2-1, V2-2, V2-3. . . valve

V3-1, V3-2, V3-3. . . valve

V4-1, V4-2, V4-3. . . valve

W. . . Semiconductor wafer

1 is a schematic view showing the overall structure of a polishing apparatus according to an embodiment of the present invention;

2 is a cross-sectional view showing a top ring constituting a substrate holding device, the top ring holding a semiconductor wafer as an object to be polished, and pressing the semiconductor wafer against an abrasive surface on the polishing table;

Figure 3 is a schematic cross-sectional view showing the main structural elements of the top ring;

Figure 4 is a cross-sectional view showing an experimental apparatus for measuring the temperature of a wafer, the temperature of a film, the temperature of a carrier, and the like when a semiconductor wafer (substrate) is heated and cooled. By;

Figure 5 is a diagram showing the lower surface of a semiconductor wafer (substrate) when it is heated by forced heating by using the experimental apparatus shown in Fig. 4, and then cooled by forced cooling. a graph of the time variable;

Figures 6A and 6B are graphs drawn using all of the time-series data shown in Figure 5, where the infrared temperature measurements are plotted on a horizontal axis and simultaneously measured by a thermocouple. The film upper surface temperature measurement is plotted on the vertical axis;

Figures 7A and 7B are diagrams in which the infrared temperature measurement correction value is plotted on the horizontal axis, and the film upper surface temperature measurement measured by the thermocouple is plotted on the vertical axis;

Figures 8A and 8B are diagrams in which the film temperature estimates calculated from a film temperature estimation equation are plotted on the horizontal axis, while the film upper surface temperature measurement measured by the thermocouple is drawn. On the vertical axis;

Figure 9 is a graph showing the results, wherein the film temperature is estimated from the infrared temperature measurement value shown in Figure 5 and the measured temperature value of the vehicle using a multiple linear regression equation;

Figure 10 is a graph drawn using all of the time series data shown in Figure 5, where the film temperature estimates calculated from the film temperature estimation equation are plotted on the horizontal axis while the crystal is measured by the thermocouple. The measurement of the temperature of the lower surface of the circle is plotted on the vertical axis;

Figure 11 is a graph in which the wafer temperature measurement is plotted on the horizontal axis, while the lower surface temperature measurement measured by the thermocouple is plotted on the vertical axis;

Figure 12 is a graph showing the results, wherein the wafer temperature is estimated from the infrared temperature measurement value shown in Figure 5 and the temperature measurement value of the vehicle using a multiple linear regression equation;

Figure 13 is a view showing one of the aspects of the polishing apparatus according to the present invention, estimating the wafer temperature by the infrared temperature measurement value and the vehicle temperature measurement value, for determining the grinding conditions and the processes of the similar ones. flow chart;

Figure 14A is an enlarged view of a portion XIV of Figure 2, and Figure 14B is a view showing a piping system for supplying nitrogen gas having atmospheric pressure to the pressure chamber;

Figure 15 is a schematic cross-sectional view of the top ring, the top ring having a structure for performing temperature control of the pressure chamber;

Figure 16 is a plan view showing a configuration of a slurry supply nozzle for supplying a slurry (grinding liquid), the polishing pad, and the top ring;

Figure 17 is a plan view showing an example of a temperature control device of the polishing pad;

Figure 18 is a plan view showing an example of another temperature control device of the polishing pad;

Figure 19 is a plan view showing an example of a dress load and/or a change in the scanning speed;

Figure 20 is a plan view showing an example of changing the position at which the slurry falls depending on the temperature of the wafer;

Figure 21 is a plan view showing an example in which the temperature (distribution) measurement of the polishing pad is performed simultaneously with the wafer temperature measurement, and the temperature control is performed based on the measured result;

Figure 22 is a cross-sectional view showing a more detailed structure of the top ring having the infrared thermometer and the thermocouple capable of measuring the temperature of the carrier.

1. . . Top ring

2. . . Top ring

3. . . M

25. . . Rotary joint

50. . . Controller

100. . . Grinding table

100a. . . Axle

101. . . Abrasive pad

101a. . . Abrasive pad surface

102. . . nozzle

110. . . Top ring head

111. . . Top ring axle

112. . . Rotating sleeve

113. . . Synchronous wheel

114. . . Top ring motor

115. . . Timing belt

116. . . Synchronous wheel

117. . . Top ring head shaft

124. . . Vertical moving mechanism

126. . . Bearing

128. . . Bridge

129. . . Support stage

130. . . Rod

132. . . Ball screw

132a. . . Screw shaft

132b. . . Nut

138. . . AC servo motor

Q. . . Slurry

W. . . Semiconductor wafer

Claims (20)

A polishing apparatus for polishing a substrate, comprising: a polishing table having an abrasive surface; a substrate holding device configured to fix the substrate and press the substrate against the polishing surface; and a controller; The substrate holding device comprises: an elastic film configured to form a substrate holding surface to be in contact with the substrate; a carrier disposed above the elastic film; at least one pressure chamber formed in the Between the elastic film and the carrier; and an infrared detector configured to measure thermal energy from the elastic film; wherein the controller uses the measured value of the infrared detector to calculate the Estimated temperature of the elastic film. The polishing apparatus of claim 1, wherein the controller uses the temperature estimation value of the elastic film to calculate a temperature estimation value of the substrate. The polishing apparatus according to claim 1, wherein the temperature estimation value of the elastic film is used to change the grinding condition. The polishing apparatus of claim 1, wherein the infrared detector comprises an infrared thermometer. A substrate holding device capable of fixing a substrate and pressing the substrate against a The abrasive surface comprises: an elastic film configured to form a substrate holding surface to be in contact with the substrate; a carrier disposed above the elastic film; at least one pressure chamber formed in the Between the elastic film and the carrier; and an infrared detector configured to measure thermal energy from the elastic film; wherein surface roughening is applied to the back side of the substrate holding surface of the elastic film. The substrate holding device of claim 5, wherein at least two pressure chambers are formed between the elastic film and the carrier, and the infrared detector is disposed at least in the at least two pressure chambers. A pressure room. The substrate holding device according to claim 5, wherein the substrate holding surface of the elastic film for forming the pressure chamber in which the infrared detector is disposed is not provided with an opening. The substrate holding device of claim 5, wherein the infrared detector comprises an infrared thermometer. A substrate holding device for fixing a substrate and pressing the substrate against an abrasive surface, comprising: an elastic film configured to form a substrate holding surface to be in contact with the substrate; and a carrier Provided above the elastic film; At least one pressure chamber formed between the elastic film and the carrier; and an infrared detector configured to measure thermal energy from the elastic film; and a measuring instrument configured The back surface side of the substrate holding surface of the elastic film is configured to measure thermal energy of a portion other than the elastic film. The substrate holding device of claim 9, wherein the measuring instrument measures the thermal energy of the carrier. The substrate holding device of claim 9, further comprising a pressure sensor configured to measure the pressure of the pressure chamber. The substrate holding device of claim 9, further comprising a controller configured to utilize the infrared detector measurement value and the measurement value of the measuring instrument to calculate an estimate of the temperature of the elastic film value. The substrate holding device of claim 12, wherein the plurality of sets of the elastic film temperature measurement value, the infrared detector measurement value (T ₁ ), and the measuring instrument measurement value are prepared in advance ( T ₂ ); calculated by minimization (multiple linear regression equation represented by (elastic film temperature estimation) = b ₀ + b ₁ × T ₁ + b ₂ × T ₂ (elastic film temperature measurement - elastic film temperature estimation) Value) ² regression coefficients b ₀ , b ₁ and b ₂ ; and using the following equation: (elastic film temperature estimate) = b ₀ + b ₁ × (elastic film temperature measurement) + b ₂ × (Measuring instrument measurements) to calculate elastic film temperature estimates. The substrate holding device of claim 12, wherein the controller uses the temperature estimation value of the elastic film and the measuring instrument to calculate a temperature estimation value of the substrate. The substrate holding device according to claim 14, wherein a plurality of sets of the substrate temperature measurement value, the elastic film temperature estimation value (T ₁ ), and the measuring instrument measurement value (T ₂ ) are prepared in advance. The regression coefficient of the minimization (substrate temperature measurement - substrate temperature estimation) ² is calculated from the multiple linear regression equation represented by (substrate temperature estimation value) = b ₀ + b ₁ × T ₁ + b ₂ × T ₂ b ₀ , b ₁ and b ₂ ; and calculate the substrate temperature using the following equation: (substrate temperature estimate) = b ₀ + b ₁ × (elastic film temperature estimate) + b ₂ × (measuring instrument measurement) estimated value. The substrate holding device of claim 9, wherein at least two pressure chambers are formed between the elastic film and the carrier, and the infrared detector is disposed at least in the at least two pressure chambers. A pressure room. The substrate holding device according to claim 9, wherein the substrate holding surface of the elastic film for forming the pressure chamber in which the infrared detector is disposed is not provided with an opening. The substrate holding device of claim 9, wherein the infrared detector comprises an infrared thermometer. A polishing apparatus comprising: a polishing table having an abrasive surface; and a substrate holding device for fixing the substrate and pressing the substrate against an abrasive surface; comprising: an elastic film configured to form a substrate holding surface and contacting the substrate; a carrier disposed above the elastic film; at least one pressure chamber formed between the elastic film and the carrier; and an infrared detector It is configured to measure thermal energy from the elastic film; wherein surface roughening is applied to the back side of the substrate holding surface of the elastic film. A polishing apparatus comprising: a polishing table having an abrasive surface; and a substrate holding device for fixing the substrate and pressing the substrate against an abrasive surface; comprising: an elastic film configured to form a substrate holding surface and contacting the substrate; a carrier disposed above the elastic film; at least one pressure chamber formed between the elastic film and the carrier; an infrared detector; Configuring to measure thermal energy from the elastic film; A measuring instrument is disposed on the back side of the substrate holding surface of the elastic film and configured to measure thermal energy in addition to the elastic film portion.