JP5775797B2 - Polishing apparatus and method - Google Patents

Description

  The present invention relates to a polishing apparatus and method for pressing a substrate such as a semiconductor wafer against a polishing pad on a polishing table and polishing the surface to be polished by relative movement of the surface to be polished and the polishing pad. The present invention relates to a polishing apparatus and method capable of controlling the temperature of the surface (polishing surface) of a polishing pad by blowing gas onto the surface.

  In recent years, with higher integration and higher density of semiconductor devices, circuit wiring has become increasingly finer and the number of layers of multilayer wiring has increased. When trying to realize multilayer wiring while miniaturizing the circuit, the step becomes larger while following the surface unevenness of the lower layer, so as the number of wiring layers increases, the film coverage to the step shape in thin film formation (Step coverage) deteriorates. Therefore, in order to obtain a multi-layer wiring, it is necessary to improve the step coverage and perform a flattening process in an appropriate process. Further, since the depth of focus becomes shallower as the optical lithography becomes finer, it is necessary to planarize the surface of the semiconductor device so that the uneven steps on the surface of the semiconductor device are kept below the depth of focus.

Accordingly, in the semiconductor device manufacturing process, a planarization technique for the surface of the semiconductor device is becoming increasingly important. Among the planarization techniques, the most important technique is chemical mechanical polishing (CMP). In this chemical mechanical polishing, a polishing apparatus (slurry) containing abrasive grains such as silica (SiO ₂ ) and ceria (CeO ₂ ) is supplied to a polishing pad using a polishing apparatus, and a substrate such as a semiconductor wafer is removed. Polishing is carried out by being brought into sliding contact with the polishing pad.

  A polishing apparatus that performs the above-described CMP process includes a polishing table having a polishing pad, and a substrate holding device called a top ring or a polishing head for holding a semiconductor wafer (substrate). When polishing a semiconductor wafer (substrate) using such a polishing apparatus, a polishing liquid (slurry) is supplied from a polishing liquid supply nozzle to a polishing pad while holding the semiconductor wafer by a substrate holding apparatus, and the semiconductor The wafer is pressed against the surface (polishing surface) of the polishing pad with a predetermined pressure. At this time, by rotating the polishing table and the substrate holding device, the semiconductor wafer comes into sliding contact with the polishing surface, and the surface of the semiconductor wafer is polished to a flat and mirror surface.

JP 2007-181910 A Japanese Patent No. 2999397

In the above-described CMP process, it is known that step characteristics such as dishing and erosion are highly dependent on the temperature of the polishing pad.
Also, the dependency of the polishing rate on the temperature of the polishing pad has been confirmed, and there is a temperature range that provides an optimal polishing rate by the CMP process, which is optimal for obtaining a long optimal polishing rate during polishing. It is necessary to maintain the temperature of the polishing pad.
Therefore, the inventors previously injected gas from the gas injection nozzle toward the polishing pad during polishing of the substrate in Japanese Patent Application No. 2011-158080 (filed on July 19, 2011), A polishing apparatus was proposed in which the surface (polishing surface) of the polishing pad was cooled.

  As described above, the polishing apparatus polishes the substrate by rotating the polishing table while supplying the polishing liquid (slurry) from the polishing liquid supply nozzle onto the polishing pad, and is thus supplied onto the polishing pad. There is a problem that the mist of the slurry is scattered around. In addition, after polishing the substrate, the polishing table was rotated while supplying pure water from the polishing liquid supply nozzle onto the polishing pad to perform water polishing or cleaning, so that the substrate was supplied onto the polishing pad. There is a problem that mist such as pure water is scattered around. In this way, the inside of the polishing apparatus is in an environment where mist and water droplets such as slurry and pure water scatter, and the mist such as scattered slurry adheres to the surface of the parts in the polishing apparatus and becomes powder when dried. It falls on the surface of the polishing pad and causes scratches on the substrate surface.

  Since the gas injection nozzle proposed in Japanese Patent Application No. 2011-158080 is attached to a manifold disposed above the polishing pad, a large number of parts such as nozzles and nozzle mounting parts face the polishing pad. Has been placed. Therefore, the slurry adheres to these many parts, and as a result, there is a possibility that the frequency leading to generation of powder and generation of scratches on the substrate surface may increase.

  The present invention has been made in view of the above circumstances, and during the polishing of a substrate such as a semiconductor wafer, a gas is blown onto the polishing pad by a nozzle to control the temperature of the surface (polishing surface) of the polishing pad, thereby allowing dishing and erosion. There are provided a polishing apparatus and method that can improve the step characteristics by reducing the amount of adhesion of the polishing liquid (slurry) on the polishing pad to the nozzles and nozzle mounting components. For the purpose.

In order to achieve the above object, a polishing apparatus of the present invention supplies a polishing liquid to a polishing pad in a polishing apparatus that presses a substrate to be polished against a polishing pad on a polishing table to polish the surface to be polished. A pad temperature adjusting mechanism that has at least one gas injection nozzle that injects gas toward the polishing pad during polishing of the substrate, and adjusts the temperature of the polishing pad by blowing gas to the polishing pad; An atomizer having at least one nozzle for injecting a liquid or a mixed fluid of gas and liquid and spraying the liquid or the mixed fluid on the polishing pad to remove foreign matters on the polishing pad; and the pad temperature adjusting mechanism and the atomizer Is formed as an integral unit.

According to the polishing apparatus of the present invention, during polishing of a substrate such as a semiconductor wafer, the surface (polishing surface) of the polishing pad is cooled by injecting gas from at least one gas injection nozzle toward the polishing pad. Can do. Therefore, the surface of the polishing pad can be controlled to an optimum temperature in accordance with the CMP process, the polishing rate can be improved, and dishing and erosion can be prevented to improve the step characteristics.
In addition, according to the present invention, the pad temperature adjusting mechanism that adjusts the temperature of the polishing pad by blowing gas to the polishing pad and the atomizer that removes the foreign matter on the polishing pad by blowing liquid or mixed fluid to the polishing pad are integrated. By configuring as a unit, the number of parts can be reduced, the surface area of the unit can be drastically reduced, and the adhesion of dirt can be reduced. The pad temperature adjusting mechanism and the atomizer can be used individually or simultaneously.

According to a preferred aspect of the present invention, the pad temperature adjusting mechanism includes a fluid supply path that supplies gas to the gas injection nozzle.
According to a preferred aspect of the present invention, the atomizer includes a fluid supply path for supplying a liquid or a mixed fluid to the nozzle.

According to a preferred aspect of the present invention, the gas injection direction of the at least one gas injection nozzle is not perpendicular to the surface of the polishing pad, but is inclined toward the rotation direction of the polishing pad. .
According to the present invention, the polishing pad can be cooled with a high cooling capacity by inclining the gas injection direction of at least one gas injection nozzle toward the rotation direction of the polishing pad. This is because the sprayed area can be secured larger by tilting than in the vertical case. In addition, when sprayed vertically, there is a concern about slurry scattering due to rebounding, but slanting can suppress slurry scattering. Furthermore, by inclining the gas injection direction toward the rotation direction of the polishing pad, the influence of the gas injection on the slurry flow can be reduced.
According to the present invention, the polishing pad can be cooled with high cooling capacity by setting the angle formed by the gas injection direction of the gas injection nozzle and the surface of the polishing pad to, for example, 30 ° to 50 °. This is because the sprayed area can be secured and the air volume can be effectively acted on. If it is smaller than 30 °, the sprayed area becomes large, but the air volume is reduced and the cooling effect is reduced.

According to a preferred aspect of the present invention, a concentric circle passing through a point immediately below the at least one gas injection nozzle and centering on the rotation center of the polishing pad is drawn, and a tangential direction at the point immediately below the concentric circle is defined on the polishing pad. When the rotational tangential direction is defined, the gas injection direction of the at least one gas injection nozzle is inclined to the rotation center side of the polishing pad with respect to the rotational tangential direction.
According to the present invention, the polishing pad can be cooled with a high cooling capacity by inclining the gas injection direction of at least one gas injection nozzle toward the rotation center side of the polishing pad with respect to the rotational tangential direction. This is because the substrate polishing region on the polishing pad is donut-shaped (annular), and the nozzle is tilted toward the rotation center side of the polishing pad with respect to the rotation tangential direction so that gas can be injected along the donut-shaped region. This is for efficiently cooling the substrate polishing region.
According to the present invention, the polishing pad can be cooled with a high cooling capacity by setting the angle of the gas injection direction of the gas injection nozzle with respect to the rotational tangential direction to, for example, 15 ° to 35 °. This is because it becomes possible to secure the sprayed area in the substrate polishing region, and when the angle is 35 ° or more, the slurry dropping position is disturbed.

According to a preferred aspect of the present invention, the jet direction of the liquid or mixed fluid in the nozzle of the atomizer is substantially perpendicular to the surface of the polishing pad.
According to the present invention, the impact force when the liquid or mixed fluid hits the surface of the polishing pad is increased by making the ejection direction of the liquid or mixed fluid in the nozzle of the atomizer substantially perpendicular to the surface of the polishing pad. And high detergency can be demonstrated.

According to a preferred aspect of the present invention, the pad temperature adjusting mechanism and the atomizer are provided on a beam-like member extending substantially radially from the outer periphery to the center of the polishing pad above the polishing pad. And
According to the present invention, since both the pad temperature adjusting mechanism and the atomizer are provided on the beam-like member, the surface area of the entire unit can be reduced, and the amount of dirt attached can be reduced. The beam-like member, which is an elongated member, is divided into left and right parts, one side is provided with a fluid supply path and gas injection nozzle for the pad temperature adjustment mechanism, and the other is provided with a fluid supply path and nozzle for the atomizer Thus, the temperature adjustment mechanism and the atomizer can be configured as an integral unit, and a very simple structure can be achieved, thereby reducing the surface area of the entire unit.
The beam member is supported by a fixing arm on the outer peripheral side of the polishing table, and the fixing arm extends to the outside of the polishing table and is fixed to an apparatus frame or the like. Therefore, the beam-like member can be configured as a cantilever and can extend from the outer periphery to the center of the polishing pad on the polishing pad.

According to a preferred embodiment of the present invention, the beam-like member, the gas ejection direction of the gas injection nozzle, characterized in that a gas jet nozzle cover.
According to the present invention, due to the provision of the gas injection nozzle cover so as to cover the upper side of the gas injection nozzle, it is possible to flow a gaseous jet from the gas injection nozzle toward the polishing pad without diffusing efficiently polished The pad can be cooled.

According to a preferred aspect of the present invention, the gas injection nozzle cover is inclined with respect to the surface of the polishing pad so as to approach the surface of the polishing pad as the distance from the beam-shaped member increases. To do.
According to the present invention, the gas spray nozzle cover is inclined downward so as to gradually approach the polishing pad in accordance with the gas spray direction of the gas spray nozzle, so that the gas sprayed from the gas spray nozzle is not diffused. Therefore, the polishing pad can be efficiently cooled.

According to the onset bright, the polishing apparatus presses the substrate to be polished to a polishing pad on the polishing table for polishing a surface to be polished of the substrate, at least one gas jet nozzle for jetting a gas toward the polishing pad A pad temperature adjusting mechanism that adjusts the temperature of the polishing pad by blowing gas to the polishing pad, and at least one nozzle that ejects liquid or a mixed fluid of gas and liquid toward the polishing pad. An atomizer that sprays a liquid or a mixed fluid to remove foreign matter on the polishing pad, and the pad temperature adjustment mechanism and the atomizer are formed as an integral unit, and the pad temperature adjustment mechanism and the atomizer include the polishing pad Is provided in a beam-like member extending in a substantially radial direction from the outer peripheral portion to the center portion of the polishing pad, and the beam-like member includes the gas The morphism gas jetting direction of the nozzle, the gas injection nozzle cover provided, the inside for the cover gas jet nozzle, at least one gas direction adjusting plate to control the direction of flow of the gas injected from the gas injection nozzle The gas direction adjusting plate is formed of a plate-like body extending from the gas injection nozzle cover toward the polishing pad.
According to the present invention, since the direction of the flow of the gas injected from the gas injection nozzle can be controlled by the gas direction adjusting plate, the gas can flow along the polishing pad, and the polishing pad is efficiently cooled. be able to.

According to a preferred aspect of the present invention, a concentric circle passing through a point immediately below the at least one gas direction adjusting plate and centering on the rotation center of the polishing pad is drawn, and a tangential direction at the point immediately below the concentric circle is defined as the polishing pad. The at least one gas direction adjusting plate is inclined toward the center of rotation of the polishing pad with respect to the rotational tangential direction.
According to the present invention, the gas jetted from the gas jet nozzle can be made to flow toward the center side of the polishing table by the gas direction adjusting plate.
According to the present invention, the polishing pad can be cooled with a high cooling capacity by setting the angle of the flat gas direction adjusting plate with respect to the rotational tangential direction to, for example, 15 ° to 45 °. This is because the sprayed area can be secured and cooling can be performed efficiently. If the angle is greater than 45 °, the amount of gas that collides with the gas direction adjusting plate increases, the pressure is reduced and decelerated to reduce the cooling capacity, and the reflected gas that collides with the gas direction adjusting plate reflects the slurry film thickness on the polishing pad. This is to cause disturbance at the slurry dropping position.

According to a preferred aspect of the present invention, there is provided a mechanism for adjusting the direction of the gas injection nozzle cover and / or a mechanism for adjusting the direction of the gas direction adjusting plate.
According to the present invention, the inclination of the cover for the gas injection nozzle is adjusted to an optimum inclination according to the gas entrance angle that is an angle formed by the surface (polishing surface) of the polishing pad and the gas injection direction of the gas injection nozzle. Can do.
According to the present invention, by the mechanism for adjusting the direction of the gas direction adjusting plate, the direction of the plurality of gas direction adjusting plates can be adjusted in conjunction with each other, and the direction of the plurality of gas direction adjusting plates can be individually adjusted. It can also be adjusted.

According to a preferred embodiment of the present invention, the beam-like member, on the side opposite to the side provided with the gas injection nozzle cover, characterized in that a atomizer for scattering prevention cover.
ADVANTAGE OF THE INVENTION According to this invention, when wash | cleaning a polishing pad with an atomizer, it can prevent that the fluid sprayed from an atomizer and the foreign material on a polishing pad scatter around.

According to a preferred aspect of the present invention, a control valve that controls a flow rate of gas injected from the at least one gas injection nozzle, a thermometer that detects a temperature of the polishing pad, and a control target temperature of the polishing pad A flow rate of gas injected from the at least one gas injection nozzle is controlled by adjusting a valve opening degree of the control valve by comparing a predetermined temperature with a detected temperature of the polishing pad detected by the thermometer. And a controller that performs the operation.
According to the present invention, the flow rate of the gas ejected from at least one gas ejection nozzle is controlled by the control valve, the temperature of the polishing pad is detected by the thermometer, and the set temperature which is the control target temperature of the polishing pad and the temperature The flow rate of the gas injected from at least one gas injection nozzle can be controlled by comparing the detected temperature of the polishing pad detected by the meter and adjusting the valve opening of the control valve. Therefore, the surface of the polishing pad can be controlled to an optimum temperature according to the CMP process.

The polishing method of the present invention is a polishing method for polishing a surface to be polished of a substrate by pressing a substrate to be polished against the polishing pad while supplying a polishing liquid to a polishing pad on a polishing table. A gas is jetted toward the polishing pad, and a gas direction adjusting plate provided in the vicinity of the gas jet nozzle adjusts the direction of the gas jetted from the gas jet nozzle to blow the gas onto the polishing pad. It is what.
According to the present invention, the gas direction adjusting plate can cause the gas injected from the gas injection nozzle to flow along the polishing pad, and the polishing pad can be efficiently cooled. The flow of the polishing liquid on the polishing pad can be controlled by controlling the gas flow direction with the gas direction adjusting plate.
Since the polishing rate and the flatness of the surface to be polished may vary depending on the state of the polishing liquid (amount, concentration, product, etc.), by controlling the gas flow injected from the gas injection nozzle with the gas direction adjusting plate The flow of the polishing liquid on the polishing pad is also controlled, and the polishing performance can be controlled.

According to a preferred aspect of the present invention, the flow of the polishing liquid on the polishing pad is controlled by adjusting the direction of the gas injected from the gas injection nozzle by the gas direction adjusting plate.
According to the present invention, by adjusting the direction of the gas injected from the gas injection nozzle by the gas direction adjusting plate, the disturbance of the polishing liquid on the polishing pad is alleviated during polishing, and the film thickness of the polishing liquid is substantially uniform. Can be. Therefore, the entire surface of the substrate can be uniformly polished. Also, by adjusting the direction of the gas injected from the gas injection nozzle by the gas direction adjusting plate, the polishing liquid can be flown more (or less) near the edge or center of the substrate, and the polishing rate and in-plane uniformity Gender can be controlled.

According to a preferred aspect of the present invention, the gas injection nozzle and the gas direction adjusting plate are arranged on the downstream side of the dresser in the rotational direction of the polishing table, and the downstream side of the dresser performing dressing during polishing. The flow of the polishing liquid on the polishing pad is controlled.
According to the present invention, if a dressing process using a dresser is performed during polishing, the flow of the polishing liquid is obstructed and the film thickness of the polishing liquid tends to be disturbed. By adjusting the direction of the generated gas, the flow of the polishing liquid can be controlled on the downstream side of the dresser, and thereby the film thickness of the polishing liquid can be controlled. Therefore, the film thickness of the polishing liquid disturbed in the dressing process can be made smooth, that is, the film thickness of the polishing liquid can be made almost uniform, and the entire surface of the substrate can be polished uniformly.

According to a preferred aspect of the present invention, by adjusting the direction of the gas injected from the gas injection nozzle by the gas direction adjusting plate, the polishing liquid flowing toward the outer peripheral side of the polishing pad is allowed to flow toward the center side of the polishing pad. It controls so that it may flow toward.
According to the present invention, the new slurry supplied to the polishing pad from the polishing liquid supply nozzle can be retained on the polishing pad so as not to flow down from the polishing pad without being used for polishing. Therefore, the polishing performance can be improved and the consumption of the polishing liquid can be reduced.

According to a preferred aspect of the present invention, by adjusting the direction of the gas injected from the gas injection nozzle by the gas direction adjusting plate, it is downstream of the top ring that holds the substrate in the rotation direction of the polishing table, Control is performed so that the old polishing liquid used for polishing flows toward the outer peripheral side of the polishing pad.
According to the present invention, the old polishing liquid that is located downstream of the top ring that holds the substrate in the rotation direction of the polishing table and has been used for polishing can be quickly discharged. Therefore, it is possible to prevent old polishing liquid from remaining on the polishing surface and adversely affecting the polishing rate and in-plane uniformity.

According to a preferred aspect of the present invention, the polishing liquid supply nozzle for supplying the polishing liquid to the polishing pad is made swingable, and the supply position of the polishing liquid is changed during polishing.
According to the present invention, by changing the supply position of the polishing liquid during polishing, a necessary amount of polishing liquid can be supplied to a position on the polishing pad that is most effective for polishing.

The present invention has the following effects.
(1) Two effects are expected by cooling the surface of the polishing pad during polishing.
A. The polishing rate is improved, the productivity is increased, and the cost of consumables such as a polishing liquid (slurry) per substrate can be reduced.
B. Stepping characteristics can be improved by preventing dishing and erosion.
(2) By optimizing the position where the gas is blown onto the polishing pad, a further cooling effect of the polishing pad can be expected, and further dishing and erosion can be reduced.
(3) A pad temperature adjusting mechanism that adjusts the temperature of the polishing pad by blowing gas to the polishing pad and an atomizer that sprays a liquid or mixed fluid on the polishing pad to remove foreign matters on the polishing pad are configured as an integrated unit. Therefore, three effects are expected.
A. The number of parts can be reduced, the surface area of the unit can be reduced, and the adhesion of dirt can be reduced.
B. The assembly of the unit becomes easy and the reproducibility of the assembly is improved. If the position of the nozzle changes, there is a possibility that the process will be affected, so it is important to improve the reproducibility of the assembly.
C. The unit mounting space is reduced, and the space above the polishing table can be used effectively.
(4) Since the gas temperature adjusting plate for controlling the gas flow direction is provided in the pad temperature adjusting mechanism in addition to the gas injection nozzle, three effects are expected.
A. During polishing, the disturbance of the polishing liquid on the polishing pad can be alleviated and the film thickness of the polishing liquid can be made substantially uniform.
B. A larger amount (or less) of the polishing liquid can be allowed to flow near the edge or center of the substrate, and the polishing rate and in-plane uniformity can be controlled.
C. Since the old slurry used for polishing can be quickly discharged from the polishing pad and kept on the polishing pad so that the new slurry does not flow down from the polishing pad, it is possible to improve the polishing performance and improve the polishing liquid. Consumption can be reduced.

FIG. 1 is a schematic perspective view showing the overall configuration of a polishing apparatus according to the present invention. FIG. 2 is a plan view showing a positional relationship among a polishing pad, a polishing liquid supply nozzle, a top ring, a dresser, and a pad adjusting device on the polishing table. FIG. 3 is a perspective view of the pad adjusting device. 4 is a cross-sectional view taken along line IV-IV in FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a view showing a gas direction adjusting plate installed on the lower surface of the gas injection nozzle cover. FIG. 7 is a perspective view showing the pad temperature adjusting mechanism of the pad adjusting device and the control device of the atomizer. FIG. 8 is a schematic plan view showing the relationship between the gas injection nozzle of the pad temperature adjusting mechanism and the polishing pad. FIG. 9 is a schematic side view showing the relationship between the gas injection nozzle of the pad temperature adjusting mechanism and the polishing pad. FIG. 10A is a graph showing the cooling capacity when the gas injection direction of the gas injection nozzle is not inclined with respect to the rotational tangent direction of the polishing pad and when it is inclined toward the pad center side. FIG. 10B is a graph showing the relationship between the gas entry angle representing the angle formed by the surface (polishing surface) of the polishing pad and the gas injection direction of the gas injection nozzle and the cooling capacity. FIG. 11 is a view for explaining the flow of the polishing liquid (slurry) dropped on the polishing pad from the polishing liquid supply nozzle, FIG. 11 (a) is a perspective view, FIG. 11 (b) is a plan view, FIG. 11C is an elevation view. FIG. 12 is a diagram for explaining the flow of the polishing liquid (slurry) dropped on the polishing pad from the polishing liquid supply nozzle when both the top ring and the dresser are operating, and FIG. Is a perspective view, FIG. 12B is a plan view, and FIG. 12C is an elevation view. FIG. 13 is a schematic diagram for explaining a method of controlling the flow of the polishing liquid (slurry) by the gas injection nozzle and the gas direction adjusting plate in the pad temperature adjusting mechanism, and FIG. 13 (a) is a plan view. 13 (b) is an elevation view, and FIG. 13 (c) is a side view. FIG. 14 is a diagram showing a case where a plurality of gas direction adjusting plates are directed in different directions, and FIG. 14 (a) is a schematic diagram showing the relationship between the direction of the gas direction adjusting plate and the slurry film thickness. FIG. 14B is a schematic diagram showing the relationship between the polishing liquid (slurry) on the polishing pad and the substrate held by the top ring. FIG. 15 is a diagram showing a mechanism for adjusting the direction of the gas direction adjusting plate, and FIG. 15A is a schematic diagram showing a mechanism for independently controlling the gas guide angles of a plurality of gas direction adjusting plates. FIGS. 15B and 15C are schematic views showing a mechanism for controlling the gas guide angles of a plurality of gas direction adjusting plates in conjunction with each other. FIG. 16 is a schematic diagram illustrating an example in which the angle of the cover for the gas injection nozzle can be adjusted. FIG. 17 is a schematic plan view showing a state in which the polishing liquid (slurry) dropped on the polishing pad from the polishing liquid supply nozzle flows out of the top ring and then is discharged from the polishing pad. FIG. 18 is a schematic diagram showing the flow of fresh slurry and used slurry dropped on the polishing pad. FIG. 19 is a schematic plan view for explaining a method of controlling the flow of slurry by the gas injection nozzle and the gas direction adjusting plate. FIG. 20 is a schematic plan view showing an example in which a gas injection nozzle and a gas direction adjusting plate are also provided on the opposite side of the main body portion to promote discharge of old slurry used for polishing.

  Hereinafter, embodiments of a polishing apparatus and method according to the present invention will be described in detail with reference to FIGS. 1 to 20, the same or corresponding components are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a schematic perspective view showing the overall configuration of a polishing apparatus according to the present invention. As shown in FIG. 1, the polishing apparatus includes a polishing table 1 and a top ring 10 that holds a substrate W such as a semiconductor wafer that is an object to be polished and presses the substrate W against a polishing pad on the polishing table. The polishing table 1 is connected to a polishing table rotating motor (not shown) disposed below the table via a table shaft, and is rotatable around the table shaft. A polishing pad 2 is attached to the upper surface of the polishing table 1, and the surface of the polishing pad 2 constitutes a polishing surface 2a for polishing the substrate W. For the polishing pad 2, SUBA800, IC-1000, IC-1000 / SUBA400 (double-layer cloth) manufactured by Rodel, etc. are used. SUBA800 is a nonwoven fabric in which fibers are hardened with urethane resin. IC-1000 is a hard foamed polyurethane, a pad having a large number of fine holes on its surface, and is also called a perforated pad. A polishing liquid supply nozzle 3 is installed above the polishing table 1, and the polishing liquid (slurry) is supplied to the polishing pad 2 on the polishing table 1 by the polishing liquid supply nozzle 3. The rear end of the polishing liquid supply nozzle 3 is supported by a shaft 4, and the polishing liquid supply nozzle 3 can swing around the shaft 4.

  The top ring 10 is connected to a shaft 11, and the shaft 11 moves up and down with respect to the support arm 12. The entire top ring 10 is moved up and down relative to the support arm 12 by the vertical movement of the shaft 11. The shaft 11 is rotated by driving a polishing head rotating motor (not shown). The top ring 10 rotates around the shaft 11 by the rotation of the shaft 11.

The top ring 10 can hold a substrate W such as a semiconductor wafer on its lower surface. The support arm 12 is configured to be rotatable about a shaft 13, and the top ring 10 holding the substrate W on the lower surface can be moved from the substrate receiving position to above the polishing table 1 by the rotation of the support arm 12. ing. The top ring 10 holds the substrate W on the lower surface and presses the substrate W against the surface (polishing surface) 2 a of the polishing pad 2. At this time, the polishing table 1 and the top ring 10 are respectively rotated, and a polishing liquid (slurry) is supplied onto the polishing pad 2 from a polishing liquid supply nozzle 3 provided above the polishing table 1. For the polishing liquid, a polishing liquid containing silica (SiO ₂ ) or ceria (CeO ₂ ) as abrasive grains is used. In this way, while supplying the polishing liquid onto the polishing pad 2, the substrate W is pressed against the polishing pad 2 to move the substrate W and the polishing pad 2 relative to each other to polish the insulating film, metal film, etc. on the substrate. .

  As shown in FIG. 1, the polishing apparatus includes a dressing device 15 for dressing the polishing pad 2. The dressing device 15 includes a dresser arm 16, a dresser 17 that is rotatably attached to the tip of the dresser arm 16, and a dresser head 18 that is connected to the other end of the dresser arm 16. The lower part of the dresser 17 is constituted by a dressing member 17a. The dressing member 17a has a circular dressing surface, and hard particles are fixed to the dressing surface by electrodeposition or the like. Examples of the hard particles include diamond particles and ceramic particles. A motor (not shown) is built in the dresser arm 16, and the dresser 17 is rotated by this motor. The dresser head 18 is supported by a shaft 19.

  When dressing the polishing surface 2 a of the polishing pad 2, the polishing pad 2 is rotated, the dresser 17 is rotated by a motor, the dresser 17 is then lowered by an elevating mechanism, and the dressing member 17 a on the lower surface of the dresser 17 is rotated. The polishing pad 2 is brought into sliding contact with the polishing surface. By swinging (swinging) the dresser arm 16 in this state, the dresser 17 located at the tip of the dresser arm 16 can move across from the outer peripheral end of the polishing surface of the polishing pad 2 to the center. By this swinging operation, the dressing member 17a can dress the entire polishing surface of the polishing pad 2 including its center.

  As shown in FIG. 1, the polishing apparatus includes a pad temperature adjusting mechanism that adjusts the temperature of the surface (polishing surface) 2 a of the polishing pad 2 by blowing gas onto the polishing pad 2, and a liquid such as pure water on the polishing pad 2. The pad adjusting device 20 is provided with an atomizer that is sprayed onto the polishing pad 2 to remove foreign matter on the polishing pad 2. The pad adjusting device 20 is disposed above the polishing pad 2 and is disposed so as to extend in a substantially radial direction of the polishing pad 2 in parallel with the surface (polishing surface) 2 a of the polishing pad 2.

FIG. 2 is a plan view showing a positional relationship among the polishing pad 2, the polishing liquid supply nozzle 3, the top ring 10, the dresser 17, and the pad adjusting device 20 on the polishing table 1. As shown in FIG. 2, the top ring 10 and the dressing apparatus 15 and the pad adjustment device 20, arranged to 3 divided circumferentially space on the polishing pad 2 around the rotational center C _T of the polishing table 1 Has been. The top ring 10 and the pad adjustment device 20 is disposed on opposite sides of the rotational center C _T of the polishing table 1. The polishing liquid supply nozzle 3 is disposed adjacent to a top ring 10 and the pad adjustment device 20, the slurry dropping position is set in the vicinity of the rotation center C _T of the polishing table 1. The polishing liquid supply nozzle 3 can swing around the shaft 4 so that the dropping position of the polishing liquid (slurry) can be changed during polishing.

  Next, the detailed structure of the pad adjusting device 20 will be described with reference to FIGS. FIG. 3 is a perspective view of the pad adjustment device 20. As shown in FIG. 3, the pad adjusting device 20 includes a main body 21 made of a beam-like member extending in the substantially radial direction of the polishing pad 2 from the outer periphery to the center of the polishing pad 2 above the polishing pad 2, and the main body 21 includes a gas injection nozzle cover 35 fixed to one side of the main body 21 and a scattering prevention cover 40 fixed to the other side of the main body 21. The main body 21 is fixed to the apparatus frame F or the like by a fixing arm 60 extending to the outside of the polishing table 1.

  4 is a cross-sectional view taken along line IV-IV in FIG. As shown in FIG. 4, the main body portion 21 has a substantially rectangular cross section, and a pad temperature for adjusting the temperature of the surface (polishing surface) 2 a of the polishing pad 2 by blowing gas on the polishing pad 2 therein. An adjusting mechanism 22 and an atomizer 30 that removes foreign matters on the polishing pad 2 by spraying a liquid such as pure water onto the polishing pad 2 are provided. That is, the pad temperature adjusting mechanism 22 and the atomizer 30 are formed as a single unit. In FIG. 4, when a vertical one-dot chain line illustrated in the approximate center of the main body 21 is a center line CL, the pad temperature adjusting mechanism 22 is disposed on the right side and the atomizer 30 is disposed on the left side with respect to the center line CL. ing. The pad temperature adjusting mechanism 22 includes a fluid supply path 23 formed of a circular hole formed in the main body 21, and the fluid supply path 23 supplies compressed air from a compressed air source (not shown). ing. The fluid supply path 23 extends to the base end in the longitudinal direction of the main body 21. A gas injection nozzle 24 is formed obliquely below the fluid supply path 23, and compressed air is injected from the gas injection nozzle 24 and sprayed onto the surface (polishing surface) 2 a of the polishing pad 2. . The gas injection nozzle 24 is constituted by a nozzle hole communicating with the fluid supply path 23, and the nozzle hole is formed by a circular through hole or an oval through hole. A plurality of gas injection nozzles 24 are formed at predetermined intervals along the longitudinal direction of the main body 21.

  On the other hand, the atomizer 30 includes fluid supply paths 31 and 32 formed of circular holes formed in the upper and lower portions in the main body 21, and the upper fluid supply path 31 is connected to a pure water source (not shown), The fluid supply path 32 communicates with the upper fluid supply path 31. The upper and lower fluid supply paths 31 and 32 extend to the base end in the longitudinal direction of the main body 21. A nozzle 33 is disposed below the lower fluid supply path 32. A plurality of nozzles 33 are arranged at predetermined intervals along the longitudinal direction of the main body 21. Each nozzle 33 has a small-diameter nozzle hole 33h, and the nozzle hole 33h extends downward so as to be substantially orthogonal to the surface (polishing surface) 2a of the polishing pad 2. The pure water supplied from the pure water source to the upper fluid supply path 31 is supplied to the nozzle 33 via the lower fluid supply path 32.

As shown in FIG. 4, the fluid supply path for supplying pure water to the nozzle 33 is divided into an upper fluid supply path 31 and a lower fluid supply path 32, and the cross-sectional area of the lower fluid supply path 32 is set to the upper fluid. It is set smaller than the cross-sectional area of the supply path 31. As described above, the pure water is supplied from the upper fluid supply path 31 to the nozzle 33 via the lower fluid supply path 32, and the pure water is jetted from the small diameter nozzle hole 33h. The fluid is gradually throttled by gradually reducing the cross-sectional area of the flow path from the supply path 31 to the nozzle hole 33h via the lower fluid supply path 32. Thereby, the flow path loss is reduced as much as possible, and pure water is efficiently sprayed from the nozzle 33 to the polishing pad 2.
A liquid such as pure water is supplied from the liquid source to the upper fluid supply path 31, and a gas such as nitrogen (N ₂ ) gas is supplied from the gas source to the lower fluid supply path 32. The gas-liquid mixed fluid may be ejected from the nozzle 33 after mixing in the mixing space provided in the section 21.

5 is a cross-sectional view taken along line VV in FIG. As shown in FIG. 5, a fluid supply path 23 extending in the longitudinal direction of the main body 21 is formed in the main body 21. The fluid supply path 23 extends to the base end of the main body 21, and a joint 25 having a compressed air supply port 25 a is fixed to the open end of the fluid supply path 23. A plurality of gas injection nozzles 24 are formed at predetermined intervals along the longitudinal direction of the main body 21.
Although not shown in FIG. 5, the upper and lower fluid supply paths 31 and 32 of the atomizer 30 also extend in the longitudinal direction of the main body 21. The upper fluid supply path 31 extends to the base end of the main body 21, and a joint 34 having a pure water supply port 34 a is fixed to the open end of the upper fluid supply path 31.
In addition, the fluid supply paths 23, 31, and 32 are configured as one common fluid supply path, and the gas injection nozzle 24 and the nozzle 33 are provided in one fluid supply path, and an appropriate fluid supply source (compressed air source, pure water source, or the like) ) And switching the opening and closing of each nozzle hole.

Next, the gas injection nozzle cover 35 fixed to one side of the main body 21 and the scattering prevention cover 40 fixed to the other side of the main body 21 will be described.
As shown in FIG. 3, the gas injection nozzle cover 35 is attached to one side portion of the main body portion 21, and the gas injection nozzle cover 35 extends from the front end portion to the rear end portion on the side of the main body portion 21. Yes. A plurality of triangular gas direction adjusting plates 36 are provided on the lower surface of the gas injection nozzle cover 35 (described later). As shown in FIG. 4, the gas injection nozzle cover 35 is fixed to the main body 21 slightly above the gas injection nozzle 24, and extends obliquely downward along the gas injection direction of the gas injection nozzle 24. That is, the gas injection nozzle cover 35 extends obliquely downward from the fixing portion 35a slightly above the gas injection nozzle 24, and approaches the polishing surface 2a of the polishing pad 2 as the distance from the fixing portion 35a increases. However, there is a gap G1 between the tip 35e of the gas injection nozzle cover 35 and the polishing surface 2a of the polishing pad 2 to ensure a flow path of the injected air (compressed air).

  As shown in FIGS. 3 and 4, the anti-scattering cover 40 is attached to the main body 21 at a position opposite to the gas injection nozzle cover 35. The anti-scattering cover 40 includes a front cover 40a extending downward from the main body 21 at a position from the front end portion to the substantially central portion of the main body portion 21 and a horizontal direction at a position from the substantially central portion to the rear end portion of the main body portion 21. The rear cover 40b extends downward in a generally triangular shape and then extends downward. However, there is a gap G2 between the lower end 40e of the anti-scattering cover 40 and the polishing surface 2a of the polishing pad 2 to ensure a flow path of the pure water to be injected. The rear cover 40b may have a shape extending in the horizontal direction at a position from the front end portion to the rear end portion of the main body portion 21.

  FIG. 6 is a view showing the gas direction adjusting plate 36 installed on the lower surface of the gas injection nozzle cover 35. As shown in FIG. 6, a plurality of triangular gas direction adjusting plates 36 are provided at predetermined intervals on the lower surface of the gas injection nozzle cover 35. Each gas direction adjusting plate 36 is formed of a triangular plate-like body extending in the vertical direction toward the polishing pad 2. The lower end 36e of the gas direction adjusting plate 36 and the tip 35e of the gas spray nozzle cover 35 are flush with each other, and between the lower end 36e of the gas direction adjusting plate 36 and the polishing surface 2a of the polishing pad 2. Has a gap G1. Thus, by providing a plurality of gas direction adjusting plates 36 on the lower surface of the gas injection nozzle cover 35, adjustment (control) is performed so that air (compressed air) injected from the gas injection nozzle 24 flows in a predetermined direction. can do.

  In the embodiment shown in FIGS. 3 to 6, a pad temperature adjusting mechanism 22 including a fluid supply path 23 and a gas injection nozzle 24, a fluid supply path 31, and a fluid supply path are provided in a main body 21 formed of a beam-shaped member. By providing the atomizer 30 composed of the nozzle 32 and the nozzle 33, the pad temperature adjusting mechanism 22 and the atomizer 30 are formed as an integral unit. However, the pad temperature adjusting mechanism 22 is formed by configuring the fluid supply path 23 with a pipe and the gas injection nozzle 24 with a separate nozzle fixed to the fluid supply path 23, and the fluid supply path 31 and the fluid The supply path 32 is constituted by pipes, these pipes are communicated by short pipes, and the nozzle 33 is constituted by a separate nozzle fixed to the fluid supply path 32 to form the atomizer 30, and the pad temperature The pad temperature adjusting mechanism 22 and the atomizer 30 can also be formed as an integral unit by accommodating the adjusting mechanism 22 and the atomizer 30 in the cover.

  FIG. 7 is a perspective view showing the pad temperature adjustment mechanism 22 of the pad adjustment device 20 and the control device of the atomizer 30. As shown in FIG. 7, a polishing pad 2 is affixed to the upper surface of the polishing table 1. A top ring 10 is disposed above the polishing pad 2, and the top ring 10 holds the substrate W (see FIG. 1) and presses the substrate W against the polishing pad 2. The pad temperature adjusting mechanism 22 is connected to a compressed air source by a compressed air supply line 45. The compressed air supply line 45 is provided with a pressure control valve 46, and the pressure and flow rate are controlled by the compressed air supplied from the compressed air source passing through the pressure control valve 46. The pressure control valve 46 is connected to the temperature controller 47. The compressed air may be at room temperature or cooled to a predetermined temperature.

  As shown in FIG. 7, a radiation thermometer 48 that detects the surface temperature of the polishing pad 2 is installed above the polishing pad 2. The radiation thermometer 48 is connected to the temperature controller 47. A set temperature, which is a control target temperature of the polishing pad 2, is input to the temperature controller 47 from a CMP controller that controls the entire polishing apparatus. The set temperature can also be directly input to the temperature controller 47. The temperature controller 47 opens the pressure control valve 46 by PID control according to the difference between the set temperature of the polishing pad 2 input to the temperature controller 47 and the actual temperature of the polishing pad 2 detected by the radiation thermometer 48. The flow rate of the compressed air injected from the gas injection nozzle 24 is controlled by adjusting the degree. As a result, compressed air having an optimum flow rate is blown from the gas injection nozzle 24 to the polishing surface 2 a of the polishing pad 2, and the temperature of the polishing surface 2 a of the polishing pad 2 reaches the target temperature (set temperature) set by the temperature controller 47. Maintained.

  As shown in FIG. 7, the atomizer 30 is connected to a pure water supply source by a pure water supply line 49. A control valve 50 is provided in the pure water supply line 49. A control signal is input to the control valve 50 from the CMP controller, and the flow rate of pure water injected from the nozzle 33 is controlled. As a result, pure water having an optimum flow rate is sprayed onto the polishing surface 2a of the polishing pad 2 to remove foreign matters (such as a polishing pad pad and an abrasive liquid adhering substance) on the polishing pad. In addition, when injecting mixed fluid from the nozzle 33, the atomizer 30 is also connected to a gas source.

8 and 9 are views showing the relationship between the gas injection nozzle 24 of the pad temperature adjusting mechanism 22 and the polishing pad 2, FIG. 8 is a schematic plan view, and FIG. 9 is a schematic side view. 8 and 9, the atomizer 30 is not shown. As shown in FIG. 8, the pad temperature adjustment mechanism 22 includes a plurality of gas injection nozzles 24 arranged at predetermined intervals in the longitudinal direction of the main body portion 21 (in the illustrated example, eight nozzles are attached). ing). During polishing, the polishing pad 2 rotates clockwise about the rotational center C _T. In FIG. 8, the nozzles are numbered in ascending order of 1, 2, 3... 8 from the inside of the pad. For example, the third and sixth gas injection nozzles 24 will be described as an example. That is, the third and through the point P1, P2 directly under the sixth two gas injection nozzles 24, draw a concentric circle C1, C2 about the _{C T,} the tangential direction at the point P1, P2 on the concentric circle C1, C2 Is defined as the rotational tangential direction of the polishing pad, the gas injection direction of the gas injection nozzle 24 is inclined by a predetermined angle (θ1) toward the center of the pad with respect to the rotational tangential direction of the polishing pad. The gas injection direction refers to the direction of the center line of the angle (gas injection angle) at which the gas spreads in a fan shape from the gas injection nozzle port. Similarly, the nozzles other than the third and sixth nozzles are also inclined by a predetermined angle (θ1) toward the pad center with respect to the rotational tangent direction of the polishing pad. The angle (θ1) of the gas injection direction of the gas injection nozzle 24 with respect to the rotational tangential direction of the polishing pad is set to 15 ° to 35 ° in relation to the nozzle cooling capacity (described later). In addition, although the case where there are a plurality of nozzles has been described here, the number of nozzles may be one.

  As shown in FIG. 9, the gas injection direction of the gas injection nozzle 24 is not perpendicular to the surface (polishing surface) 2 a of the polishing pad 2 but is inclined by a predetermined angle toward the rotation direction of the polishing table 1. . The angle of the gas injection direction of the gas injection nozzle 24 relative to the surface (polishing surface) 2 a of the polishing pad 2, that is, the angle formed by the surface (polishing surface) 2 a of the polishing pad 2 and the gas injection direction of the gas injection nozzle 24 is entered into the gas. When defined as an angle (θ2), the gas entry angle (θ2) is set to 30 ° to 50 ° in relation to the nozzle cooling capacity (described later). Here, the gas injection direction refers to the direction of the center line of the angle (gas injection angle) at which the gas spreads in a fan shape from the gas injection nozzle port.

  Further, as shown in FIG. 9, since the main body 21 is configured to be movable up and down, the height (H) of the main body 21 is variable, and the polishing pad surface (polishing surface) of the gas injection nozzle 24 ) It is possible to adjust the height from 2a. Although FIG. 8 illustrates the case where the number of the gas injection nozzles 24 is 8, the number of nozzles can be adjusted by closing the nozzle holes with plugs or the like. is there. The number of nozzles is appropriately selected according to the cooling capacity for cooling the polishing pad 2.

  FIG. 10A shows the case where the gas injection direction of the gas injection nozzle 24 is not inclined with respect to the rotational tangential direction of the polishing pad (θ1 = 0 °) and the case where it is inclined toward the pad center side (θ1 = 15 °, θ1). = 30 °) is a graph showing the cooling capacity. In FIG. 10A, the vertical axis represents the difference (° C.) between the pad temperature without cooling and the pad temperature with cooling using the nozzle, and this difference represents the cooling capacity of the nozzle. As shown in FIG. 10A, the cooling capacity tends to improve as the angle (θ1) of the gas injection direction of the gas injection nozzle 24 with respect to the rotational tangential direction of the polishing pad increases. However, if the angle (θ1) is too large, the slurry dripping state is disturbed, so the angle (θ1) is preferably in the range of 15 ° to 35 °.

  FIG. 10B shows that the gas entry angle (θ2) representing the angle between the surface (polishing surface) 2a of the polishing pad 2 and the gas injection direction of the gas injection nozzle 24 is θ2 = 30 °, θ2 = 50 °, θ2 It is a graph which shows the cooling capacity in 70 degrees. In FIG. 10B, the vertical axis represents the difference (° C.) between the pad temperature without cooling and the pad temperature with cooling using the nozzle, and this difference represents the cooling capacity of the nozzle. As shown in FIG. 10B, the cooling capacity tends to improve as the gas entry angle (θ2) increases. However, if the angle (θ2) is too large, the slurry dripping state is disturbed, so the angle (θ2) is preferably in the range of 30 ° to 50 °.

Next, a method of controlling the flow of the polishing liquid (slurry) on the polishing pad 2 by the gas direction adjusting plate 36 that controls the flow direction of the air (compressed air) injected from the gas injection nozzle 24 of the pad temperature adjusting mechanism 22. Will be explained.
FIGS. 11A and 11B are views for explaining the flow of the polishing liquid (slurry) dropped from the polishing liquid supply nozzle 3 onto the polishing pad 2, FIG. 11A is a perspective view, and FIG. FIG. 11 and FIG. 11C are elevation views.
As shown in FIG. 11A, the polishing liquid (slurry) is dropped from the tip of the polishing liquid supply nozzle 3 to the center of the polishing pad 2. This dropping position is in the vicinity of the top ring 10. As shown in FIG. 11B, the polishing liquid (slurry) dropped on the polishing pad 2 spreads uniformly toward the outer peripheral side of the polishing pad 2 due to the centrifugal force generated by the rotation of the polishing table 1. Then, as shown in FIG. 11 (c), it spreads over the entire polishing surface 2 a of the polishing pad 2 with a substantially uniform film thickness and flows into the lower portion of the top ring 10. As a result, the polishing liquid (slurry) spreads uniformly over the entire surface to be polished of the substrate W held on the top ring 10.

FIG. 12 is a diagram for explaining the flow of the polishing liquid (slurry) dropped on the polishing pad 2 from the polishing liquid supply nozzle 3 when both the top ring 10 and the dresser 17 are operating. 12 (a) is a perspective view, FIG. 12 (b) is a plan view, and FIG. 12 (c) is an elevation view.
As shown in FIG. 12A, the polishing liquid (slurry) is dropped from the tip of the polishing liquid supply nozzle 3 to the center of the polishing pad 2. This dropping position is in the vicinity of the top ring 10. As shown in FIGS. 12B and 12C, the polishing liquid dropped on the polishing pad 2 tends to spread toward the outer peripheral side of the polishing pad 2 due to the centrifugal force generated by the rotation of the polishing table 1. When a dressing process is performed by the dresser 17 during polishing, the flow of the polishing liquid (slurry) is obstructed and flows into the lower portion of the top ring 10 in a state where the slurry film thickness is disturbed. As a result, the amount of the polishing liquid (slurry) becomes excessive or insufficient depending on the region of the surface to be polished of the substrate W, and the polishing state becomes unstable.

Therefore, in the present invention, the flow of the polishing liquid (slurry) is controlled by the gas injection nozzle 24 and the gas direction adjusting plate 36 in the pad temperature adjusting mechanism 22.
FIG. 13 is a schematic diagram for explaining a method of controlling the flow of the polishing liquid (slurry) by the gas injection nozzle 24 and the gas direction adjusting plate 36 in the pad temperature adjusting mechanism 22, and FIG. FIG. 13 (b) is an elevation view, and FIG. 13 (c) is a side view.
As shown in FIG. 13A, the polishing liquid dropped onto the polishing pad 2 tends to spread toward the outer peripheral side of the polishing pad 2 by the centrifugal force generated by the rotation of the polishing table 1, but the dresser 17 is being polished during polishing. When the dressing process is performed, the flow of the polishing liquid (slurry) is obstructed and the slurry film thickness is disturbed. Therefore, as shown in FIGS. 13A and 13B, the flow direction of the air (compressed air) injected from the gas injection nozzle 24 on the downstream side of the dresser 17 in the rotational direction of the polishing table 1 is gas. Control is performed by the direction adjusting plate 36.

Here, the gas direction adjusting plate 36 located on the innermost side of the polishing pad 2 will be described as an example. Through the point P3 just below the proximal end of the gas direction adjusting plate 36, drawing a concentric C3 around the rotation center C _T of the polishing pad 2, the tangential direction of rotation of the polishing pad tangential at the point P3 on the concentric circle C3 When defined, the flat gas direction adjusting plate 36 is inclined by a predetermined angle (θ3) toward the center of the pad with respect to the rotational tangent direction of the polishing pad. If this angle (θ3) is defined as a gas guide angle, it is preferable to adjust the gas guide angle (θ3) to a range of 15 ° to 45 ° during polishing. The same applies to the gas guide angle (θ3) of the other gas direction adjusting plate 36.

  FIG. 13C is a diagram showing a state in which the flow of the slurry can be influenced by controlling the direction of the flow of the air (compressed air) by the gas direction adjusting plate 36. Although the slurry film thickness on the polishing pad 2 was disturbed in the figure, the slurry film was controlled as shown in the lower figure of FIG. 13C by controlling the air flow with the gas direction adjusting plate 36. The thickness becomes smooth, that is, becomes almost uniform. Thus, according to the present invention, by adjusting the gas guide angle (θ3) of the gas direction adjusting plate 36, the disturbance of the polishing liquid (slurry) on the polishing pad 2 is alleviated and the film thickness of the polishing liquid is reduced. It can be made almost uniform.

In the example shown in FIG. 13, the case where the plurality of gas direction adjusting plates 36 are directed in the same direction is illustrated, but the slurry film thickness is changed by directing the plurality of gas direction adjusting plates 36 in different directions. You can also.
FIG. 14 is a diagram showing a case where a plurality of gas direction adjusting plates 36 are directed in different directions, and FIG. 14A shows the relationship between the direction of the gas direction adjusting plate 36 and the slurry film thickness. FIG. 14B is a schematic diagram showing the relationship between the polishing liquid (slurry) on the polishing pad 2 and the substrate W held by the top ring 10.

  As shown in FIG. 14A, by directing the plurality of gas direction adjusting plates 36 in different directions, the air (compressed air) injected from the gas injection nozzle 24 is controlled to flow in different directions. can do. Thus, in the upper diagram of FIG. 14A, the slurry film thickness on the polishing pad 2 is uniform, but as shown in the lower diagram of FIG. Changes in thickness can be given. In this way, by changing the slurry film thickness, as shown in FIG. 14B, the portion with the thin slurry film thickness is made to correspond to the central portion of the substrate W, and the portion with the large slurry film thickness is By making it correspond to the outer peripheral portion, the polishing rate of the outer peripheral portion of the substrate can be higher than the polishing rate of the central portion of the substrate. Conversely, the polishing rate at the central portion of the substrate is adjusted to correspond to the outer peripheral portion of the substrate by making the portion with the thin slurry film thickness correspond to the outer peripheral portion of the substrate W and the portion with the thick slurry film thickness to correspond to the central portion of the substrate W. The polishing rate can be increased.

  As described above, according to the present invention, the polishing rate can be increased by flowing the slurry more or less near the edge of the substrate or near the center by individually adjusting the gas guide angle (θ3) of the gas direction adjusting plate 36. And in-plane uniformity can be controlled.

FIG. 15 is a view showing a mechanism for adjusting the direction of the gas direction adjusting plate 36, and FIG. 15A shows a mechanism for independently controlling the gas guide angles (θ3) of the plurality of gas direction adjusting plates 36. FIG. 15B and FIG. 15C are schematic views showing a mechanism for controlling the gas guide angle (θ3) of the plurality of gas direction adjusting plates 36 in conjunction with each other.
In the example shown in FIG. 15A, one side of the triangular gas direction adjusting plate 36 is fixed to a shaft 37, and the upper end of the shaft 37 is connected to a servo motor or a rotary actuator 38. With this configuration, when the servo motor or the rotary actuator 38 is operated, the gas direction adjusting plate 36 swings around the shaft 37, and the gas guide angle (θ3) of the gas direction adjusting plate 36 can be changed. In the example shown in FIG. 15A, the plurality of gas direction adjusting plates 36 are individually controlled by a servo motor or a rotary actuator 38. Instead of the servo motor or the rotary actuator, each shaft 37 may be manually rotated and then fixed with screws.

  In the example shown in FIG. 15B, the plurality of gas direction adjusting plates 36 are respectively fixed to the shafts 37, and the pinions 51 are fixed to the upper ends of the shafts 37. The plurality of pinions 51 are engaged with a single rack 52, and the rack 52 is connected to a cylinder, a linear motor, or a linear actuator 53. With this configuration, when the cylinder, the linear motor, or the linear actuator 53 is operated, the rack 52 moves forward or backward to rotate the pinion 51, and the gas direction adjusting plate 36 swings around the shaft 37. The 36 gas guiding angles (θ3) can be changed. In the example shown in FIG. 15B, the plurality of gas direction adjusting plates 36 are controlled by a cylinder, a linear motor, or a linear actuator 53 in conjunction with each other. Instead of the cylinder, servo motor, or rotary actuator, the rack 52 may be manually operated and then fixed with screws.

  In the example shown in FIG. 15C, the gas direction adjusting plate 36 is not shown, and only the mechanism for driving the plurality of shafts 37 is shown. As shown in FIG. 15C, the plurality of shafts 37 are respectively connected to one end of the arm 61. The other ends of the plurality of arms 61 are connected to a link 63 via a connecting pin 62. Each shaft 37 is held by a bearing or the like so that movement is restricted and only rotation is allowed. With this configuration, when the link 63 is linearly reciprocated by a cylinder, a linear motor, an actuator (not shown) or the like, the plurality of arms 61 swing around the shaft 37, so the shaft 37 is fixed. The end portion side of the arm 61 that is a portion to be rotated rotates. Therefore, the shaft 37 rotates around the axis and the gas guide angle (θ3) of the gas direction adjusting plate 36 can be changed.

FIG. 16 is a schematic diagram illustrating an example in which the angle of the gas injection nozzle cover 35 can be adjusted. 3 to 5, the gas injection nozzle cover 35 is fixed to the main body 21, but in the example shown in FIG. 16, the end of the gas injection nozzle cover 35 is fixed to the shaft 42. Yes. The shaft 42 is rotatably supported by two brackets 43 and 43 extending from the main body 21 (not shown) of the pad adjusting device 20. Further, the end of the shaft 42 is connected to a servo motor or a rotary actuator 44. With this configuration, when the servo motor or the rotary actuator 44 is operated, the gas injection nozzle cover 35 swings around the shaft 42 and the vertical inclination of the gas injection nozzle cover 35 can be changed. Thereby, according to the gas entrance angle (θ2) (see FIG. 9) that is an angle formed between the surface (polishing surface) 2 a of the polishing pad 2 and the gas injection direction of the gas injection nozzle 24, The inclination can be adjusted to an optimum inclination.
For example, when the gas injection nozzle 24 is fixed and the gas discharge direction cannot be changed, or when the supplied gas is at a constant flow rate, the gas injection nozzle cover 35 moves, so that the gas directed toward the surface 2a of the polishing pad 2 is moved. The amount of cooling can be changed by changing the amount. Further, the gas injection nozzle cover 35 is opened, so that the function of guiding the gas in the gas injection nozzle cover 35 is lost, and the gas injection nozzle cover 35 causes the gas to flow toward the surface 2 a of the polishing pad 2. The slurry can be made to flow toward the top ring 10 while changing the thickness of the slurry with the gas direction adjusting plate 36.
The configuration of the gas direction adjusting plate 36 inside the gas injection nozzle cover 35 is as shown in FIGS.

Next, the flow of the polishing liquid (slurry) on the polishing pad 2 is controlled by the gas direction adjusting plate 36 that controls the flow direction of the air (compressed air) injected from the gas injection nozzle 24 of the pad temperature adjusting mechanism 22. A method for controlling the amount of slurry consumed will be described.
FIG. 17 is a schematic plan view showing a state in which the polishing liquid (slurry) dropped from the polishing liquid supply nozzle 3 onto the polishing pad 2 flows out of the top ring 10 and then is discharged from the polishing pad 2. In this case, it is preferable to supply as much fresh slurry dropped on the polishing pad 2 as possible to the surface to be polished of the substrate held by the top ring 10 and to quickly discharge the old slurry used for polishing. This is because if the fresh slurry is discharged without being used for polishing, the consumption of the slurry increases, and if the old slurry remains, the polishing rate and in-plane uniformity are adversely affected.

  FIG. 18 is a schematic diagram showing the flow of fresh slurry and used slurry dropped on the polishing pad 2. As shown in FIG. 18, the slurry is discharged from the outer peripheral portion of the polishing pad 2, but a relatively new slurry is discharged on the upstream side of the top ring 10 in the rotation direction of the polishing table 1. There is much discharge of relatively old slurry immediately downstream of the top ring 10 in the direction. Therefore, if the slurry discharged from the region A indicated by the dotted line in FIG. 18 can be used for polishing, the amount of slurry consumption can be reduced.

Therefore, in the present invention, the flow of the slurry is controlled by the gas injection nozzle 24 and the gas direction adjusting plate 36 so as to eliminate or reduce the slurry discharged from the region A as much as possible.
FIG. 19 is a schematic plan view for explaining a method of controlling the flow of slurry by the gas injection nozzle 24 and the gas direction adjusting plate 36. As shown in FIG. 19, the flow direction of the air (compressed air) injected from the gas injection nozzle 24 by adjusting the gas guide angle (θ3), which is the angle of the gas direction adjusting plate 36 with respect to the rotational tangential direction. The slurry is left on the polishing pad 2 by controlling the slurry flowing toward the outer peripheral side of the polishing pad 2 so as to flow toward the center side of the polishing pad 2. Thereby, the slurry discharged | emitted from the area | region A can be eliminated or it can reduce as much as possible.

  FIG. 20 is a schematic plan view showing an example in which the gas injection nozzle 24 and the gas direction adjusting plate 36 are also provided on the opposite side of the main body portion 21 to promote the discharge of old slurry used for polishing. As shown in FIG. 20, the gas injection nozzles 24 and the gas direction adjusting plates 36 are provided on both sides of the main body portion 21, and air is injected from the gas injection nozzles 24 on both sides of the main body portion 21 so that the gas directions on both sides of the main body portion 21. The adjustment plate 36 controls the air flow. That is, the gas injection nozzle 24 and the gas direction adjusting plate 36 on the upstream side in the rotation direction of the polishing table 1 inject air (compressed air) on the opposite side (opposite side) to the rotation direction of the polishing table 1. The air flow is controlled. Thus, the discharge of the old slurry is promoted with the air flow direction directed toward the outer peripheral side of the polishing table 1. That is, the old slurry that is downstream of the top ring 10 in the rotation direction of the polishing table 1 and used for polishing is discharged by air and centrifugal force.

On the other hand, the gas injection nozzle 24 and the gas direction adjusting plate 36 on the downstream side in the rotation direction of the polishing table 1 jet air in the rotation direction of the polishing table 1 to control the flow of air. By adjusting the gas guide angle (θ3) of the gas direction adjusting plate 36, the direction of air flow is directed toward the inner side of the polishing table 1, and the slurry flowing toward the outer peripheral side of the polishing pad 2 is moved toward the center side of the polishing pad 2 So that the slurry remains on the polishing pad 2. As a result, the slurry discharged from the region A shown in FIG. 18 can be eliminated or minimized. In this way, by adjusting the wind direction of the cooling air jetted from the gas jet nozzle 24 to quickly discharge the old slurry and prevent the new slurry on the supply side from flowing down from the polishing pad 2, the amount of slurry consumed Can be drastically reduced.

  In the embodiment shown in FIGS. 11 to 20, the case where the flow of the polishing liquid (slurry) on the polishing pad 2 is controlled by air (compressed air) has been mainly described, but the gas injection nozzle 24 is directed toward the polishing pad 2. The temperature of the polishing surface 2a of the polishing pad 2 is controlled to a desired temperature by the air jetted in the same manner as in the embodiment shown in FIGS.

Next, an example of a process for polishing the substrate W using the polishing apparatus configured as shown in FIGS. 1 to 20 will be described.
First, a first set temperature that is a control target temperature of the polishing pad 2 is set in the temperature controller 47. Next, the supply pressure for supplying the compressed air to the gas injection nozzle 24 is confirmed. When the supply pressure is lower than the specified pressure, a warning is issued and the subsequent processing for the substrate is stopped. Only when the supply pressure is higher than the specified pressure, the substrate W is removed from the pusher by the top ring 10 positioned at the substrate delivery position. Receive and hold. Then, the substrate W sucked and held by the top ring 10 is horizontally moved from the substrate delivery position to the polishing position directly above the polishing table 1.

  Next, temperature monitoring of the polishing pad 2 by the radiation thermometer 48 is started. Then, a polishing liquid (slurry) is dropped from the polishing liquid supply nozzle 3 onto the polishing pad 2, and the top ring 10 is lowered while rotating, so that the surface of the substrate W (polishing target) on the polishing surface 2 a of the rotating polishing pad 2. Surface). Then, the adsorption of the substrate W by the top ring 10 is released, and the substrate W is pressed against the polishing surface 2a with the first polishing pressure. Thereby, a main polishing step for polishing a metal film or the like on the substrate is started.

  In the main polishing step, temperature control of the polishing pad 2 by the pad temperature adjusting mechanism 22 of the pad adjusting device 20 is started from the time when the substrate W comes into contact with the polishing surface 2a. In the case where a process of bringing the substrate W into contact with the polishing surface 2a without rotating the polishing table 1 is adopted, the polishing of the polishing pad 2 by the pad temperature adjusting mechanism 22 is started at the same time as the rotation of the polishing table 1 is started. Start temperature control.

  That is, the temperature controller 47 adjusts the valve opening degree of the pressure control valve 46 by PID control according to the difference between the preset first set temperature and the actual temperature of the polishing pad 2 detected by the radiation thermometer 48. The flow rate of the compressed air injected from the gas injection nozzle 24 is controlled. Thus, the temperature of the polishing pad 2 is controlled to the first set temperature at which the maximum polishing rate obtained in advance is obtained. In this main polishing step, a high polishing rate can be obtained by a combination of a high polishing pressure and cooling of the polishing pad 2, and the total polishing time can be shortened.

  In parallel with the above process, the polishing liquid supply nozzle 3 is swung to supply the polishing liquid (slurry) to the optimum position on the polishing pad 2 and is injected from the gas injection nozzle 24 by the gas direction adjusting plate 36. By controlling the flow of air, the flow of the polishing liquid (slurry) on the polishing pad 2 is controlled so that the film thickness of the slurry flowing toward the top ring 10 is uniform, and in-plane uniformity is obtained. To be able to. This main polishing step ends when, for example, a film thickness measuring device (not shown) installed in the polishing table 1 detects that the film thickness of a metal film or the like has reached a predetermined value.

  Next, a finish polishing step is performed. In the final polishing step after the main polishing step, it is necessary to control the temperature of the polishing pad 2 in order to prevent dishing, erosion, and the like and attach importance to improving the step characteristics. That is, the second set temperature, which is a temperature different from the first set temperature, is set in the temperature controller 47. When the process proceeds to the final polishing step, compressed air having a flow rate controlled by PID control is sprayed onto the polishing pad 2 so that the polishing pad 2 quickly reaches the second set temperature. For example, when the second set temperature of the finish polishing step is lower than the first set temperature of the main polishing step, the flow rate of the compressed air is controlled to be MAX (maximum) until the second set temperature is reached. Is done. In this way, polishing is continued by controlling the temperature of the polishing pad 2 to the second set temperature. In this final polishing step, the substrate W is pressed against the polishing surface 2a with a second polishing pressure lower than the first polishing pressure, if necessary, in order to mainly improve the level difference elimination characteristics. In parallel with the above process, the polishing liquid supply nozzle 3 is swung to supply the polishing liquid (slurry) to the optimum position on the polishing pad 2 and the gas injection nozzle 24 and the gas direction adjusting plate 36 are connected to the organic solvent. By operating in an automatic manner, the polishing rate and in-plane uniformity are controlled by causing the slurry to flow more (or less) near the substrate edge or the center. In this final polishing step, for example, a surplus metal film or the like in a region other than the trench or the like is removed by polishing, and a film thickness measuring device (see FIG. It ends when it detects in (not shown).

  Next, after the jet of compressed air from the gas injection nozzle 24 is stopped and the supply of the polishing liquid (slurry) from the polishing liquid supply nozzle 3 is stopped, pure water is supplied to the polishing pad 2 and the substrate W Perform water polishing. Then, the ejection of the compressed air from the gas injection nozzle 24 is stopped, and the polished substrate W is separated from the polishing surface 2a by the top ring 10 while being adsorbed and held while preventing the compressed air from hitting the substrate W. In addition, since the substrate W is separated from the polishing pad 2 thereafter, the gas injection nozzle 24 prevents the compressed surface from hitting the polished surface of the separated substrate W and drying the polished surface of the substrate W. The compressed air jet is kept stopped.

  Next, the top ring 10 holding the substrate W is lifted and the substrate W is moved horizontally from the polishing position to the substrate delivery position. Then, the polished substrate W is transferred to a pusher or the like at the substrate transfer position. After the polishing is completed, pure water (or a mixed fluid of nitrogen and pure water) is sprayed from the nozzle 33 of the atomizer 30 onto the surface (polishing surface) 2a of the polishing pad 2, and foreign matters on the polishing pad (polishing pad wrinkles, abrasive liquid adhesion, etc.) ) Is removed. In the gas injection nozzle 24, cleaning gas (water) is sprayed from the cleaning nozzle (not shown) to the nozzle opening portion in the gas injection nozzle 24 and particularly toward the nozzle opening and its peripheral portion to clean the gas injection nozzle 24. . Thereby, it is possible to prevent dirt such as slurry adhering to the gas injection nozzle 24 from falling on the polishing pad 2 and adversely affecting the processing of the next substrate. Further, the gas injection nozzle cover 35 and the gas direction adjusting plate 36 are similarly cleaned. In this case, since the inside of the gas injection nozzle cover 35 and the gas direction adjusting plate 36 is open, the inside of the gas injection nozzle cover 35 and the gas direction adjusting plate 36 can be cleaned when the atomizer 30 is used.

  Although the embodiments of the present invention have been described so far, it is needless to say that the present invention is not limited to the above-described embodiments and may be implemented in various forms within the scope of the technical idea.

DESCRIPTION OF SYMBOLS 1 Polishing table 2 Polishing pad 2a Polishing surface 3 Polishing liquid supply nozzle 10 Top ring 11, 13 Shaft 12 Support arm 15 Dressing device 16 Dresser arm 17 Dresser 18 Dresser head 19 Shaft 20 Pad adjusting device 21 Pad adjusting device main body 22 Pad temperature Adjustment mechanism 23 Fluid supply path 24 Gas injection nozzle 25 Joint 25a Compressed air supply port 30 Atomizer 31, 32 Fluid supply path 33 Nozzle 33h Nozzle hole 34 Joint 34a Pure water supply port 35 Gas injection nozzle cover 36 Gas direction adjusting plate 37 Shaft 38 Servo motor or rotary actuator 40 Splash prevention cover 42 Shaft 44 Servo motor or rotary actuator 46 Pressure control valve 47 Temperature controller 48 Radiation thermometer 51 Pinion 2 racks 53 cylinders or linear motors or linear actuator 61 arm 62 connecting pin 63 link

Claims (21)

In a polishing apparatus for polishing a surface to be polished of a substrate by pressing the substrate to be polished against a polishing pad on a polishing table,
A pad temperature for supplying a polishing liquid to the polishing pad and for injecting gas toward the polishing pad during polishing of the substrate, and adjusting the temperature of the polishing pad by blowing gas to the polishing pad An adjustment mechanism;
An atomizer that has at least one nozzle that ejects liquid or a mixed fluid of gas and liquid toward the polishing pad, and sprays the liquid or mixed fluid onto the polishing pad to remove foreign matters on the polishing pad;
The polishing apparatus according to claim 1, wherein the pad temperature adjusting mechanism and the atomizer are formed as an integral unit.   The polishing apparatus according to claim 1, wherein the pad temperature adjustment mechanism includes a fluid supply path that supplies gas to the gas injection nozzle.   The polishing apparatus according to claim 1, wherein the atomizer includes a fluid supply path that supplies a liquid or a mixed fluid to the nozzle.   2. The polishing apparatus according to claim 1, wherein the gas injection direction of the at least one gas injection nozzle is not perpendicular to the surface of the polishing pad but is inclined toward the rotation direction of the polishing pad.   A concentric circle passing through a point immediately below the at least one gas injection nozzle and centering on the rotation center of the polishing pad is defined, and a tangential direction at the point immediately below the concentric circle is defined as a rotation tangent direction of the polishing pad. The polishing apparatus according to claim 1, wherein a gas injection direction of one gas injection nozzle is inclined toward a rotation center side of the polishing pad with respect to the rotation tangential direction.   The polishing apparatus according to claim 1, wherein a jet direction of the liquid or mixed fluid in the nozzle of the atomizer is substantially perpendicular to the surface of the polishing pad.   2. The polishing apparatus according to claim 1, wherein the pad temperature adjusting mechanism and the atomizer are provided on a beam-like member extending in a substantially radial direction from the outer periphery to the center of the polishing pad above the polishing pad. . Wherein the beam member, the gas ejection direction of the gas injection nozzle, the polishing apparatus according to claim 7, characterized in that a gas jet nozzle cover.   The polishing apparatus according to claim 8, wherein the gas injection nozzle cover is inclined with respect to the surface of the polishing pad so as to be closer to the surface of the polishing pad as it is separated from the beam-like member. In a polishing apparatus for polishing a surface to be polished of a substrate by pressing the substrate to be polished against a polishing pad on a polishing table,
A pad temperature adjustment mechanism having at least one gas injection nozzle for injecting gas toward the polishing pad, and adjusting the temperature of the polishing pad by blowing gas to the polishing pad;
An atomizer that has at least one nozzle that ejects liquid or a mixed fluid of gas and liquid toward the polishing pad, and sprays the liquid or mixed fluid onto the polishing pad to remove foreign matters on the polishing pad;
The pad temperature adjustment mechanism and the atomizer are formed as an integral unit,
The pad temperature adjusting mechanism and the atomizer are provided on a beam-like member extending in a substantially radial direction from the outer peripheral portion to the center portion of the polishing pad above the polishing pad,
The beam member is provided with a gas injection nozzle cover on the gas injection direction side of the gas injection nozzle,
At least one gas direction adjusting plate for controlling the direction of flow of the gas injected from the gas injection nozzle is provided inside the gas injection nozzle cover, and the gas direction adjustment plate is disposed from the gas injection nozzle cover. it characterized by comprising a plate-like body extending toward the polishing pad Migaku Ken apparatus. 11. The polishing apparatus according to claim 10, wherein the gas injection nozzle cover is inclined with respect to the surface of the polishing pad so as to approach the surface of the polishing pad as the distance from the beam-shaped member increases.   When a concentric circle passing through a point immediately below the at least one gas direction adjusting plate and centering on the rotation center of the polishing pad is drawn, and a tangential direction at the point immediately below the concentric circle is defined as a rotation tangent direction of the polishing pad, The polishing apparatus according to claim 10, wherein the at least one gas direction adjusting plate is inclined toward the rotation center side of the polishing pad with respect to the rotation tangential direction. The polishing apparatus according to any one of claims 8 to 12 , further comprising a mechanism for adjusting a direction of the cover for the gas injection nozzle and / or a mechanism for adjusting a direction of the gas direction adjusting plate. The polishing apparatus according to any one of claims 8 to 13, wherein the beam-shaped member is provided with an anti-scattering cover for an atomizer on a side opposite to the side on which the cover for the gas injection nozzle is provided. . A control valve for controlling the flow rate of gas injected from the at least one gas injection nozzle;
A thermometer for detecting the temperature of the polishing pad;
By comparing the set temperature, which is the control target temperature of the polishing pad, with the detected temperature of the polishing pad detected by the thermometer, and adjusting the valve opening of the control valve, the at least one gas injection nozzle the polishing apparatus according to any one of claims 1 to 14, characterized by comprising a controller for controlling the flow rate of the gas to be injected. In the polishing method of polishing the surface to be polished of the substrate by pressing the substrate to be polished against the polishing pad while supplying the polishing liquid to the polishing pad on the polishing table,
Injecting gas from at least one gas injection nozzle toward the polishing pad;
A polishing method, wherein a gas direction adjusting plate provided in the vicinity of the gas injection nozzle adjusts the direction of the gas injected from the gas injection nozzle and blows the gas onto the polishing pad. The polishing method according to claim 16 , wherein the flow of the polishing liquid on the polishing pad is controlled by adjusting the direction of the gas injected from the gas injection nozzle by the gas direction adjusting plate. The gas injection nozzle and the gas direction adjusting plate are arranged on the downstream side of the dresser in the rotational direction of the polishing table, and the flow of the polishing liquid on the polishing pad is downstream of the dresser performing dressing during polishing. The polishing method according to claim 17 , wherein the polishing method is controlled. By controlling the direction of the gas injected from the gas injection nozzle by the gas direction adjusting plate, the polishing liquid flowing toward the outer peripheral side of the polishing pad is controlled to flow toward the center side of the polishing pad. The polishing method according to claim 17 . By adjusting the direction of the gas injected from the gas injection nozzle by the gas direction adjustment plate, the old polishing liquid used for polishing is located downstream of the top ring that holds the substrate in the rotation direction of the polishing table. The polishing method according to claim 17 , wherein the polishing is controlled to flow toward the outer peripheral side of the polishing pad. The polishing method according to any one of claims 16 to 20, wherein the polishing liquid supply nozzle for supplying a polishing liquid to the polishing pad and swingable to change the supply position of the polishing liquid during polishing .

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