JP2001284297A - Polishing device, polishing method and manufacturing method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polishing device which can restrain damage and a polishing method, and a manufacturing method of a semiconductor device by improving polishing rate while maintaining relaxing ability of original steps. SOLUTION: A polishing device has a polishing tool 11 with a polishing surface and polishes a surface wherein a metallic film is formed on a wafer by bringing a polishing surface of the tool 11 into contact with the surface to be polished. The device has a complex formation agent supply means 71 for supplying a complex formation agent containing ligand which forms a complex of a metallic film whose mechanical strength is lower than that of the metallic film to at least a contact region between the polishing surface and the surface to be polished, and a temperature adjustment means 61 for adjusting the temperature of the complex formation reaction region at a temperature which accelerates complex formation reaction between the metallic film and the complex formation agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus, a polishing method, and a method for manufacturing a semiconductor device, which are used, for example, in a process of forming a multilayer wiring structure of a semiconductor device.

[0002]

2. Description of the Related Art As semiconductor devices become more highly integrated and miniaturized,
With the miniaturization of wiring, the reduction of wiring pitch, and the increasing of the number of wiring layers, the importance of multilayer wiring technology in the manufacturing process of semiconductor devices is increasing. On the other hand, conventionally, aluminum has been frequently used as a wiring material for a semiconductor device having a multilayer wiring structure. However, in recent design rules under the 0.18 μm rule, in order to suppress signal propagation delay, the wiring material is changed from aluminum to copper. The development of a wiring process that substitutes for is being actively pursued. When copper is used for wiring, there is an advantage that both low resistance and high electromigration resistance can be achieved.

In the process of using copper for wiring, for example, a metal is buried in a groove-shaped wiring pattern formed in advance in an interlayer insulating film, and a CMP (Chemical Mechanical Poor) is used.
A wiring process called a damascen method, in which an excess metal film is removed by a lishing (chemical mechanical polishing) method to form a wiring, has become effective. This damascene method has an advantage that the process can be simplified because the wiring does not need to be etched and the upper interlayer insulating film is naturally flat. Furthermore, not only the wiring groove but also the contact hole is formed in the interlayer insulating film as a groove, and the wiring groove and the contact hole are simultaneously filled with metal, so that the dual damascene method can further reduce the number of wiring steps. .

Here, an example of a wiring forming process by the dual damascene method will be described with reference to the following drawings.
explain. The case where copper is used as the wiring material will be described. First, as shown in FIG. 20A, an interlayer insulating film 302 made of, for example, silicon oxide is formed on a semiconductor substrate 301 made of silicon or the like on which an impurity diffusion region (not shown) is appropriately formed by, for example, low-pressure CVD ( Chemic
al Vapor Deposition) method.

Next, as shown in FIG. 20B, a contact hole CH leading to the impurity diffusion region of the semiconductor substrate 301 and a wiring having a predetermined pattern electrically connected to the impurity diffusion region of the semiconductor substrate 301 are formed. Groove M to be formed
Is formed using a known photolithography technique and etching technique.

Next, as shown in FIG. 20C, a barrier film 305 is formed on the surface of the interlayer insulating film 302, in the contact holes CH and in the trenches M. This barrier film 305
For example, a material such as Ta, Ti, TaN, or TiN is formed by a known sputtering method. When the material of the barrier film 305 is copper and the interlayer insulating film 302 is made of silicon oxide, copper has a large diffusion coefficient into silicon oxide and is easily oxidized. Is provided.

Next, as shown in FIG. 21D, a seed film 306 is formed on the barrier film 305 by depositing copper to a predetermined thickness by a known sputtering method. Next, FIG.
As shown in FIG. 1E, a copper film 307 is formed so as to fill the contact hole CH and the trench M with copper. The copper film 307 is formed by, for example, a plating method, a CVD method, a sputtering method, or the like.

Next, as shown in FIG. 21F, an extra copper film 307 and an extra barrier film 305 on the interlayer insulating film 302 are formed.
Is removed by a CMP method and planarized. Through the above steps, the copper wiring 308 and the contact 309 are formed. By repeatedly performing the above process on the wiring 308, a multilayer wiring can be formed.

[0009]

However, in the above-described copper wiring forming process using the dual damascene method,
In the step of removing the excess copper film 307 by the CMP method, in the planarization technique using the conventional CMP method, a high pressure is applied between the polishing tool and the copper film and the polishing is performed. This damage is not negligible, especially when an organic insulating film having a low mechanical strength and a low dielectric constant is used for the interlayer insulating film.
There are problems such as generation of cracks (cracks) in the interlayer insulating film and peeling of the interlayer insulating film from the semiconductor substrate.

Further, since the removal performance of the interlayer insulating film 302 is different from that of the copper film 307 and the barrier film 305, there is a problem that dishing, erosion (thinning), recess, and the like are easily generated in the wiring 308.
The dishing is performed, for example, as shown in FIG.
In the design rule of the 0.18 μm rule, for example, when a wide wiring 308 such as about 100 μm is present, the central part of the wiring is excessively removed and dented. Insufficient cross-sectional area of the wiring 308 causes a wiring resistance value defect and the like. This dishing is likely to occur when relatively soft copper or aluminum is used for the wiring material.
The erosion is, for example, as shown in FIG.
This is a phenomenon in which a high-pattern-density portion in which a wiring having a width of 1.0 μm is formed at a density of 50% in a range of 3000 μm is excessively removed. If erosion occurs, the cross-sectional area of the wiring becomes insufficient. As a result, the wiring resistance value becomes defective. The recess is a phenomenon in which the wiring 308 is lowered at the boundary between the interlayer insulating film 302 and the wiring 308 as shown in FIG.
Also in this case, since the cross-sectional area of the wiring is insufficient, the wiring resistance may be defective.

On the other hand, particularly in the damascene method or the dual damascene method, since the wiring groove or the wiring groove and the contact hole are simultaneously filled with copper, an extra copper film 307 is formed.
Is thick, and the surface of the copper film has irregularities caused by embedding. Therefore, it is necessary to reduce the initial step while efficiently removing the excess copper film 307 by the CMP method. Therefore, the polishing rate, which is the removal amount per unit time, is required to be, for example, 500 nm / min or more. In order to increase the polishing rate, it is necessary to increase the processing pressure on the wafer or to increase the etching force. It is conceivable to use a strong chemical solution or to increase the rotation speed of the polishing tool, but in any case, in terms of accuracy, when trying to improve the polishing rate by the above method,
It is known that the ability to alleviate steps (flattening ability) is reduced. In addition, as shown in FIG. 23, a scratch SC and a chemical damage CD are easily generated on the wiring surface, and particularly easily generated with soft copper. For this reason, it causes defects such as open wiring, short circuit, and poor wiring resistance value, and when trying to improve the polishing rate by the above-described method, the above cracks, peeling of the interlayer insulating film, dishing, erosion, and recess are caused. There was a disadvantage that the amount generated was also large.

The present invention has been made in view of the above-mentioned problems. Accordingly, the present invention provides a method for planarizing a metal film such as a copper wiring by polishing without causing disadvantages such as dishing and erosion. In addition, an object of the present invention is to provide a polishing apparatus, a polishing method, and a method for manufacturing a semiconductor device capable of improving a polishing rate and suppressing damage to an interlayer insulating film or the like below a wiring while maintaining a capability of alleviating a step of initial unevenness. And

[0013]

In order to achieve the above object, a polishing apparatus according to the present invention comprises a polishing section having a polishing surface, and the polishing apparatus has a polishing surface on which a metal film of an object to be polished is formed. A polishing apparatus for polishing by bringing the polishing surface of the portion into contact with the polishing surface, wherein a complex of the metal film having lower mechanical strength than the metal film is formed in at least a contact area between the polishing surface and the surface to be polished. A complex forming agent supplying means for supplying a complex forming agent containing a ligand, and a temperature adjusting means for adjusting the temperature of the complex forming reaction region to a temperature at which a complex forming reaction between the metal film and the complex forming agent is promoted. Have.

In the above polishing apparatus of the present invention, preferably, the complex forming agent contains a chemical polishing agent containing abrasive grains.

In the above polishing apparatus of the present invention, preferably, the metal film is formed of copper.

In the polishing apparatus of the present invention, preferably, the complex forming agent includes an oxidizing agent for oxidizing the metal film and promoting the complex forming reaction.

Preferably, in the above-mentioned polishing apparatus of the present invention, in the complex-forming agent supply means, at least one of a chelating agent of quinaldic acid, glycine, citric acid, oxalic acid or propionic acid is used as the ligand. Is supplied.

In the polishing apparatus of the present invention, preferably, the temperature adjusting means adjusts the temperature of the complex forming reaction region by adjusting the temperature of the complex forming agent containing the chemical polishing agent. The temperature of the complex formation reaction region is adjusted by adjusting the temperature of the polished surface or the polished surface.

Preferably, the polishing apparatus of the present invention further comprises a temperature measuring means for measuring a temperature of the complex formation reaction region, and more preferably, the temperature of the complex forming reaction region is determined based on a detection signal from the temperature measuring means. There is further provided control means for controlling the temperature adjustment means so that the value of the temperature is constant.

According to the above-described polishing apparatus of the present invention, the surface of the metal film to be polished is oxidized by the oxidizing agent to form a complex film by a complex formation reaction with the ligand. The complex membrane,
Since the mechanical strength is lower than that of the metal film, it is possible to remove by polishing at a low polishing pressure. In the above operation, since the complex film is uniformly formed on the surface of the metal film, for example, when polishing a metal film having an uneven shape, the complex film is uniformly formed on the surface of the metal film having the uneven shape, By selectively removing the convex portion of the complex film, the metal film surface of the convex portion is exposed. The convex portions of the metal film further become a complex film by the action of the complex forming agent, and are selectively removed again. As a result, the initial irregularities of the metal film are flattened. Further, by adjusting the temperature of the complex formation reaction region to a temperature at which the complex formation reaction is promoted, the formation rate of the complex film is increased, so that the polishing rate of the metal film can be improved.
Note that, based on a detection signal from a temperature measurement unit that measures the temperature of the complex formation reaction region, the above operation is controlled by the control unit so that the value of the temperature becomes constant, by controlling the temperature adjustment unit. The formation rate of the complex film can be kept almost constant, and as a result, the polishing rate can be kept constant. Therefore, a polishing apparatus having a high leveling ability can be realized.

In order to achieve the above object, a polishing method according to the present invention is a method for polishing an object to be polished having a metal film on a surface to be polished, wherein the surface to be polished is more mechanical than the metal film. Supplying a complex forming agent containing a ligand that forms a complex of the metal film having a low strength, forming a complex film on the surface of the metal film with the complex forming agent, and removing the complex film; Exposing the removed metal film under the complex film to the surface, and adjusting the temperature of the complex formation reaction region to a temperature at which a complex formation reaction between the complex forming agent and the metal film is promoted.

In the polishing method according to the present invention, preferably, after the step of removing the complex film, the complex forming agent is supplied to the exposed metal film so that the complex film is formed on the surface of the metal film. The metal film is polished by repeatedly performing a process of removing the complex film.

In the polishing method of the present invention, preferably, the surface to be polished has the metal film having an uneven shape, and in the step of forming the complex film,
In the step of forming the complex film according to the uneven shape of the metal film and removing the complex film, a convex portion of the complex film is selectively removed to expose the metal film of the convex portion to the surface. The complex forming agent is again supplied to the exposed convex portion of the metal film to form the complex film, and the step of removing the complex film is repeated to flatten and polish the metal film.

In the polishing method of the present invention, preferably, the complex forming agent contains a chemical polishing agent containing abrasive grains, and in the step of removing the complex film, the complex forming agent is removed by the chemical polishing agent. The complex film on the surface to be polished is removed by chemical mechanical polishing.

In the above polishing method of the present invention, preferably, the metal film is formed of copper.

In the above polishing method of the present invention, preferably, the complex forming agent includes an oxidizing agent that oxidizes the metal film and promotes the complex forming reaction.

In the polishing method of the present invention described above, preferably, in the step of supplying the complex-forming agent, at least one of quinaldic acid, glycine, citric acid, oxalic acid, and propionic acid is used as the ligand. In the step of supplying the complex-forming agent containing the chelating agent, and forming the complex film, a chelate film is formed as the complex film.

In the polishing method of the present invention, preferably, in the step of supplying the complex-forming agent, the complex-forming agent containing the chemical polishing agent is supplied at a controlled temperature. The temperature of the complex formation reaction region is adjusted by adjusting the temperature of the polishing target used in the step of removing the object to be polished or the complex film.

According to the polishing method of the present invention described above, the surface of the metal film to be polished is oxidized by the oxidizing agent to form a complex film by a complex formation reaction with the ligand. Since the complex film has lower mechanical strength than the metal film, it can be polished and removed at a low polishing pressure. In the above operation, since the complex film is uniformly formed on the surface of the metal film, for example, when polishing a metal film having an uneven shape, the complex film is uniformly formed on the surface of the metal film having the uneven shape, By selectively removing the convex portion of the complex film, the metal film surface of the convex portion is exposed. The convex portion of the metal film further becomes a complex film by the action of the complex forming agent, and is selectively removed again to flatten the initial unevenness of the metal film. Further, by adjusting the temperature of the complex formation reaction region to a temperature at which the complex formation reaction is promoted, the formation rate of the complex film is increased, so that the polishing rate of the metal film can be improved. In addition, by adjusting the above operation so that the temperature of the complex formation reaction region is constant, the formation rate of the complex film can be kept almost constant, and as a result, the polishing rate can be kept constant. . Therefore, a polishing method having a high leveling ability can be realized.

Further, in order to achieve the above object, a method of manufacturing a semiconductor device according to the present invention comprises the steps of: forming a wiring groove on an insulating film formed on a substrate; Depositing a metal film having an uneven shape corresponding to the step of the wiring groove on the entire surface of the insulating film, and a complex of the metal film having a lower mechanical strength than the metal film on the surface of the metal film. Supplying a complex-forming agent containing a ligand that forms a complex, forming a complex film of the metal film on the surface of the metal film with the complex-forming agent, and forming the complex according to the uneven shape of the metal film. Selectively remove the convex part of the film,
Exposing the metal film under the complex film of the convex portion to the surface, and adjusting the temperature of the complex formation reaction region to a temperature at which a complex formation reaction between the complex forming agent and the metal film is promoted.

Preferably, in the method of manufacturing a semiconductor device according to the present invention, after the step of removing the complex film, the complex forming agent is supplied to the exposed surface of the metal film to convert the complex film to the metal film. The metal film is polished by repeatedly performing a step of forming the complex film on the film surface and removing the complex film.

Preferably, in the method of manufacturing a semiconductor device according to the present invention, a copper film is deposited in the step of depositing the metal film.

Preferably, in the method for manufacturing a semiconductor device according to the present invention, after the step of forming the wiring groove, before the step of depositing the copper film, the insulating film and the inside of the wiring groove are formed. The method further includes the step of forming a conductive barrier film by coating, and in the step of depositing the copper film, the copper film is deposited on the barrier film so as to fill the wiring groove.

Preferably, in the method of manufacturing a semiconductor device according to the present invention, in the step of supplying the complex forming agent, the complex forming agent containing a chemical abrasive containing abrasive grains is supplied to form the complex film. In the removing step, the complex film is removed by chemical mechanical polishing using the chemical polishing agent.

In the method of manufacturing a semiconductor device according to the present invention, preferably, the complex forming agent includes an oxidizing agent that oxidizes the metal film and promotes the complex forming reaction.

In the method of manufacturing a semiconductor device according to the present invention, preferably, in the step of supplying the complex-forming agent, at least one of quinaldic acid, glycine, citric acid, oxalic acid and propionic acid is used as the ligand. In the step of supplying the complex forming agent containing the chelating agent to form the complex film, a chelate film is formed as the complex film.

Preferably, in the method of manufacturing a semiconductor device according to the present invention, in the step of supplying the complex forming agent, the complex forming agent including the chemical polishing agent is supplied at a controlled temperature. The temperature of the complex forming reaction region is adjusted by adjusting the temperature of the region and the temperature of the substrate on which the metal film is formed and the polishing tool used in the complex film removing step.

Preferably, in the method of manufacturing a semiconductor device according to the present invention, in the step of forming the wiring groove, the wiring groove is formed together with an impurity diffusion layer or a wiring formed below the insulating film. Forming a contact hole for connecting to a wiring formed in the wiring groove, and embedding the metal in the contact hole together with the wiring groove in the step of depositing the metal film. The insulating film is made of at least silicon oxide, fluorinated silicate glass, polyimide-based polymer compound, Teflon (registered trademark) -based polymer compound, fluorinated amorphous carbon-based compound, polyarylether-based polymer compound, HS
It is formed of a material containing either Q or xerogel. Here, HSQ stands for Hydrogen Silsequioxanes
And the chemical formula is H ₈ Si ₈ O ₁₂ .

According to the method of manufacturing a semiconductor device of the present invention described above, the surface of the metal film to be polished is oxidized by the oxidizing agent to form a complex film by a complex formation reaction with the ligand. Since the complex film has lower mechanical strength than the metal film, it can be polished and removed at a low polishing pressure. Therefore, damage to the interlayer insulating film below the metal film can be reduced, and the present invention can be applied to a low-dielectric-constant material whose mechanical strength is lower than that of silicon oxide made of TEOS or the like as an insulating film material. Further, disadvantages such as dishing and erosion can be prevented. In the above operation, since the complex film is uniformly formed on the surface of the metal film, for example, when polishing a metal film having an uneven shape, the complex film is uniformly formed on the surface of the metal film having the uneven shape, By selectively removing the convex portion of the complex film, the metal film surface of the convex portion is exposed. The convex portion of the metal film further becomes a complex film by the action of the complex forming agent, and is selectively removed again to flatten the initial unevenness of the metal film. Further, by adjusting the temperature of the complex formation reaction region to a temperature at which the complex formation reaction is promoted, the formation rate of the complex film is increased, so that the polishing rate of the metal film can be improved. Throughput can be improved. In addition, by adjusting the above operation so that the temperature of the complex formation region is constant, the formation rate of the complex film can be kept almost constant, and as a result, the polishing rate can be kept constant. Therefore, a polishing method having a high leveling ability can be realized.

[0040]

Embodiments of a polishing apparatus, a polishing method and a method of manufacturing a semiconductor device according to the present invention will be described below with reference to the drawings.

First Embodiment FIG. 1 is a view showing a configuration of a polishing apparatus according to an embodiment of the present invention. The polishing apparatus shown in FIG. 1 has a processing head section and a controller 55 having a function of controlling the entire polishing apparatus.
, A temperature controller 61, a temperature measuring device 62, a slurry supply device 71, and a pure water supply device 81. Although not shown, the polishing apparatus is installed in a clean room, and a carry-in / out port for carrying in / out a wafer cassette containing a wafer to be polished is provided in the clean room. Further, a wafer transfer robot for transferring a wafer between the wafer cassette loaded into the clean room through the loading / unloading port and the polishing apparatus is provided between the loading / unloading port and the polishing apparatus.

A polishing tool holder 10 for holding and rotating the polishing tool 11, a Z-axis positioning mechanism 30 for positioning the polishing tool holder 10 at a target position in the Z-axis direction, and a wafer W to be polished. An X-axis moving mechanism 40 that is held, rotated, and moved in the X-axis direction constitutes a processing head.

FIG. 2 is a schematic enlarged view of the processing head.
The polishing tool holder 10 includes a polishing tool 11 and a polishing tool 11.
A holding member 13 for holding the flange member 12 rotatably via a main shaft 13a;
A spindle motor 14 for rotating the spindle 13 a held by the holding device 13.

The main shaft motor 14 is, for example, a direct drive motor, and a rotor (not shown) of the direct drive motor is connected to the main shaft 13a. The spindle motor 14 is driven by a drive current supplied from a spindle driver 52.

The holding device 13 is provided with, for example, an air bearing, and the main shaft 13a is rotatably held by the air bearing.

The flange member 12 is connected to the main shaft 13a, and the polishing tool 11 is fixed to the lower end surface. Since the upper end surface of the flange member 12 is connected to the main shaft 13a, the rotation of the main shaft 13a causes the flange member 12 to also rotate.

The polishing tool 11 is fixed to the lower end surface of the flange member 12. The polishing tool 11 is formed, for example, in a wheel shape, and has an annular polishing surface 11a on the lower end surface.
It has. The polishing tool 11 is preferably formed of a relatively soft material. For example, the binder matrix (binder) itself is conductive carbon, or
It can be formed of a porous body made of a resin such as a urethane resin containing a sintered copper, a metal compound, or the like, a melamine resin, an epoxy resin, or polyvinyl acetal (PVA).

The Z-axis positioning mechanism 30 is connected to a Z-axis servomotor 31 fixed to a column (not shown), a ball screw shaft 31 a connected to the Z-axis servomotor 31, a holding device 13 and a spindle motor 14. , Ball screw shaft 3
A Z-axis slider 32 having a threaded portion screwed to
A guide rail 33 mounted on a column (not shown) for holding the shaft slider 32 movably in the Z-axis direction.

The Z-axis servomotor 31 is driven to rotate by being supplied with a drive current from a Z-axis driver 51 connected to the Z-axis servomotor 31. The ball screw shaft 31a is provided along the Z-axis direction, one end is connected to the Z-axis servo motor 31, and the other end is rotatably held by a holding member provided on the column (not shown). And Z
The screw portion of the shaft slider 32 is screwed. With the above configuration, the ball screw shaft 31a is rotated by driving the Z-axis servo motor 31, and the polishing tool 11 held by the polishing tool holding unit 10 is moved to an arbitrary position in the Z-axis direction via the Z-axis slider 32. It is moved and positioned. The positioning accuracy of the Z-axis positioning mechanism 30 is, for example, about 0.1 μm in resolution.

The X-axis moving mechanism 40 includes a wafer table 42 for chucking the wafer W and a driving motor 44 for supplying a driving force for rotating the wafer table 42.
And a belt 46 connecting the drive motor 44 and the rotating shaft of the holding device 45, and a processing pan 4 provided on the holding device 45.
7, an X-axis slider 48 on which a drive motor 44 and a holding device 45 are installed, an X-axis servo motor 49 installed on a frame (not shown), a ball screw shaft 49a connected to the X-axis servo motor 49, and X A movable member 49b connected to the shaft slider 48 and having a threaded portion screwed to the ball screw shaft 49a.

The wafer table 42 sucks the wafer W by, for example, vacuum suction means. Processing bread 47
Is provided for collecting a liquid such as used slurry. The drive motor 44 is connected to the table driver 53, is driven by a drive current supplied from the table driver 53, and controls the drive current to rotate the wafer table 42 at a predetermined rotation speed. Can be. The X-axis servo motor 49
The X-axis driver 5 is connected to the
The X-axis slider 48 is driven to rotate by the driving current supplied from the X-axis and the ball screw shaft 49a and the movable member 49b.
, And is driven in the X-axis direction. At this time, by controlling the drive current supplied to the X-axis servomotor 49,
Speed control of the wafer table 42 in the X-axis direction becomes possible.

The slurry supply device 71 supplies the slurry SL onto the wafer W via a supply nozzle. As the slurry (complex forming agent), for example, an oxidizing agent that oxidizes a metal, a ligand that forms a complex of an oxidized metal, and abrasive grains are used. The oxidizing agent is, for example, an aqueous oxidizing solution based on hydrogen peroxide, iron nitrate, potassium iodate or the like for polishing a copper film. Examples of the abrasive grains include aluminum oxide (alumina), cerium oxide (ceria), silica, and germanium oxide. As the ligand, for example, for polishing a copper film, quinaldic acid, glycine, citric acid, oxalic acid,
Use a chelating agent such as propionic acid.

The pure water supply device 81 supplies pure water H onto the wafer W via a supply nozzle. This is used for the purpose of cleaning the wafer W, cleaning the chucking surface, and the like. The spindle motor 14, the holding device 13, and the spindle 13
a and a through hole is formed in the center of the flange member 12,
A supply nozzle for supplying the slurry SL and the pure water H onto the wafer W from the through-holes is also possible.

The temperature controller 61 includes a slurry supply device 71
Further, the temperature of the slurry SL and the pure water H supplied from the pure water supply device 81 is adjusted to a constant temperature using a constant temperature bath or the like. Here, FIGS. 3 and 4 show specific examples of the configurations of the slurry supply device 71 and the temperature controller 61. FIG.

In the example shown in FIG.
Is composed of a slurry tank 71a in which an oxidizing agent, a chelating agent and abrasive grains are mixed by a stirrer S, and a pump P for supplying a slurry SL from the slurry tank 71a to a temperature controller 61 through a pipe Pi. The temperature controller 61 includes, for example, a thermostat 61a, a thermometer T for measuring the temperature of the thermostat, and a pipe P passing through the thermostat 61a.
i, the temperature of the liquid in the thermostat is kept constant. With the above configuration, the slurry SL from the slurry tank 71a is guided by the pump P to the thermostat 61a through the pipe Pi, and passes through the thermostat 61a through the pipe Pi, whereby the temperature of the slurry SL in the pipe Pi is adjusted. And the slurry SL whose temperature has been adjusted is
It is supplied to the upper processing point.

In the example shown in FIG.
Is a slurry tank 7 for separately holding polishing abrasive grains, chelating agent, and oxidizing agent, which are components in the slurry SL.
, And a pump P for supplying the slurry SL in the slurry tank to the temperature controller 61.
The temperature controller 61 takes out a mixer M for mixing the slurry supplied from each slurry tank, a heat exchanger 61b provided outside the mixer M, and a high-temperature fluid passing through the heat exchanger 61b, and adjusts the temperature. A constant temperature bath 6 having a pump P which is kept constant and is supplied to the heat exchanger 61b again
1a. In the above configuration example, the abrasive grains, the chelating agent, the oxidizing agent, and the like, which are the components in the slurry SL, are held in separate slurry tanks 71a, 71b,...
And temperature are adjusted by a mixer M having In the above configuration example, when a highly volatile hydrogen peroxide solution or the like is used by heating, or when the slurry contains a component that deteriorates with time or deteriorates with time, if the solution is left mixed, it reacts. This is effective in cases such as getting lost.
In this configuration example, each slurry tank, pump P and mixer M correspond to one specific example of the complex forming agent supply means.

The temperature measuring device 62 is provided, for example, for monitoring the temperature of the wafer W, and outputs a monitored temperature measurement signal 62 s to the controller 55. As the temperature measuring device 62, for example, an infrared surface thermometer is used.

The controller 55 has a function of controlling the entire polishing apparatus. Specifically, the controller 55 outputs a control signal 52 s to the spindle driver 52 to control the number of revolutions of the polishing tool 11, 51, a control signal 51s is output to perform positioning control of the polishing tool 11 in the Z-axis direction,
A control signal 53s is output to the table driver 53 to control the number of rotations of the wafer W, and a control signal 54s is output to the X-axis driver 54 to control the speed of the wafer W in the X-axis direction.

The controller 55 includes a temperature controller 6
1 is controlled to control the temperature adjustment of the pure water H and the slurry SL supplied to the processing head. For example, a temperature measurement signal 62s from the temperature measurement device 62 is input to the controller 55, and a control signal 61s is output using the temperature measurement signal 62s as a feedback signal so that the temperature obtained from the temperature measurement signal 62s becomes constant. Thus, the adjustment temperature in the temperature adjuster 61 is controlled.

The control panel 56 connected to the controller 55 allows the operator to input various data and display, for example, a monitored temperature measurement signal 62s.

Next, the polishing operation by the above-described polishing apparatus will be described by taking as an example a case where a metal film formed on the surface of the wafer W is polished. The case where a metal film made of, for example, a copper film is formed on the surface of the wafer W will be described. First, the wafer W is chucked on the wafer table 42, and pure water whose temperature has been adjusted by the temperature adjuster 61 from the pure water supply device 81 is supplied onto the wafer W for a certain time to adjust the temperature of the wafer W. deep. Here, for example, once every two minutes for 10 seconds (flow rate: 400 ml / min) 7
Supply pure water at 0 ° C. Also, the temperature in the clean room where the polishing apparatus is installed is controlled to a constant temperature. Next, the supply of pure water is stopped, and the wafer table 42 is driven to rotate the wafer W at a predetermined rotation speed. Also,
The wafer table 42 in the X-axis direction (indicated by an arrow x in the figure)
Then, the polishing tool 11 attached to the flange member 12 is arranged at a predetermined location above the wafer W, and the polishing tool 11 is rotated at a predetermined rotation speed.

The slurry SL whose temperature has been adjusted by the temperature adjuster 61 is supplied to the processing point of the wafer W, and the polishing tool 11 is lowered in the Z-axis direction (indicated by an arrow z in the drawing) to lower the polishing surface of the polishing tool 11. 11a is brought into contact with the surface of the wafer W and pressed at a predetermined processing pressure. From this state, the wafer table 42 is moved in the X-axis direction at a predetermined speed pattern, and the entire surface of the wafer W is uniformly polished.

In the polishing apparatus having the above-described structure, a chelate film having low mechanical strength is generated and removed on the surface of the copper film MT formed on the wafer W by using a complex forming agent such as an oxidizing agent and a chelating agent. Has functions. Further, the reaction of forming a chelate film on the surface of the copper film is promoted by supplying a slurry whose temperature is adjusted, and a high polishing rate is secured.

According to the polishing apparatus of this embodiment, since the metal film is changed to a chelate film having low mechanical strength by using a chelating agent and the copper film is polished at a low polishing pressure, disadvantages such as dishing and erosion occur. Flattening processing can be performed without occurrence. In addition, by promoting the chelation reaction between the copper film and the chelating agent by adjusting the temperature,
A high polishing rate can be secured. Furthermore, by making the temperature of the wafer surface constant by the temperature controller, the generation rate of the complex film can be kept constant, and as a result, the polishing rate of the metal film in the wafer can be kept constant. As a result, a polishing apparatus having a high leveling ability can be realized.

Modification 1 FIG. 5 is a schematic diagram showing a modification of the polishing apparatus according to the present invention. The polishing apparatus shown in FIG. 5 promotes the above complex formation reaction by adjusting the temperature of the wafer W. For example, as shown in FIG. 5, a heater is provided inside the wafer table 42 for chucking the wafer W of the polishing apparatus of the first embodiment. For example, a heating element 43 is provided in a radial shape, and the heating element 43 and the heater power supply 41 are electrically connected via a rotary joint 43. Although not shown, the heater power supply 41 and the controller 55 are connected, and the operation of the heater power supply 41 can be controlled based on a temperature measurement signal 62s from the temperature measurement device 62. More specifically, the temperature measurement signal 62s is set so that the temperature obtained from the temperature measurement signal 62s is constant.
The voltage of the heater power supply 41 is controlled using s as a feedback signal.

Further, a radial circulating water channel is provided inside the wafer table 42 for chucking the wafer W of the polishing apparatus of the first embodiment, and a constant temperature fluid is supplied and circulated by a constant temperature bath. Thereby, the temperature of the wafer W may be adjusted. Also in this case, the thermostat and the controller 55 are connected, and the operation of the thermostat can be controlled based on the temperature measurement signal 62 s from the thermometer 62. Specifically, the temperature measurement signal 62s
Temperature measurement signal 6 so that the temperature obtained from
2s is used as a feedback signal to control the temperature of the thermostat and to control the operation of the supply flow rate to the circulation channel.

The polishing operation of the polishing apparatus having the above-described configuration is basically the same as that of the first embodiment. The temperature of the wafer W is adjusted by adjusting the temperature of the wafer table 42 holding the wafer W. The temperature of the complex formation region is adjusted to promote the complex formation reaction.
In the polishing apparatus having the above configuration, a chelating film having low mechanical strength is generated on the surface of the copper film formed on the wafer W by using a complexing agent such as an oxidizing agent and a chelating agent,
Has a function to remove.

The same effect as that of the first embodiment can be achieved by the above-described polishing apparatus. Therefore, a polishing apparatus having a low polishing pressure, a high polishing rate, and a high flattening ability can be realized.

Modification 2 FIG. 6 is a schematic configuration diagram showing a modification of the polishing apparatus according to the present invention. The polishing apparatus shown in FIG. 6 is obtained by adding the function of the present invention to a conventional CMP apparatus. Conventional CM
In the P device, the surface plate 23 mounted on the spindle bearing 24
The entire surface of the wafer W chucked by the wafer chuck 21b is brought into contact with the rotating polishing surface of the polishing tool on which the polishing pad (polishing cloth) 22 is adhered while rotating, so that the surface of the wafer W is flattened. .

The polishing apparatus shown in FIG. 6 has the following configuration in addition to the above-mentioned conventional CMP apparatus. Here, for example, an apparatus for polishing a copper film on a wafer surface will be described.

First, the platen 23 has a built-in heater. For example, a heating element 23a is embedded in the platen 23 in a radial pattern. The heating element 23a and the heater power supply 41 are electrically connected via a rotary joint 43. Further, the heater power supply 41 and the controller 55 are connected, and a temperature measurement signal 62s
, The operation of the heater power supply 41 can be controlled. Specifically, the voltage of the heater power supply 41 is controlled using the temperature measurement signal 62s as a feedback signal so that the temperature obtained from the temperature measurement signal 62s becomes constant.

As in the first modification, a radial circulating water channel is installed inside the surface plate 23 to supply and circulate a fluid at a constant temperature in a thermostat.
The temperature of the wafer W may be adjusted. Also in this case, the thermostat and the controller 55 are connected, and the operation of the thermostat can be controlled based on the temperature measurement signal 62 s from the thermometer 62. Specifically, the temperature measurement signal 62
The temperature measurement signal 62s is used as a feedback signal to control the temperature of the thermostat and the operation of the supply flow rate to the circulating water channel so that the temperature obtained from s becomes constant.

The slurry supply device supplies an oxidizing agent for oxidizing the copper film, a ligand, and the like in addition to the abrasive grains. In addition,
The components of these slurries are the same as in the first embodiment. Further, a temperature controller 61 for controlling the temperature of the slurry EL and the pure water H is provided. The configurations of the slurry supply device 71 and the temperature controller 61 are the same as those in the first embodiment.

A temperature controller 61 and a controller 55 are also connected, and a temperature measurement signal 62
The operation of the temperature controller 61 can be controlled based on s. Specifically, the operation of the temperature regulator is controlled using the temperature measurement signal 62s as a feedback signal so that the temperature obtained from the temperature measurement signal 62s becomes constant.

The wafer chuck side is thermally insulated between the wafer chuck 21b and the wafer W using the heat insulating material 21a as a backing agent.
I am trying to learn the temperature.

Here, the polishing operation (polishing method) by the polishing apparatus having the above configuration will be described. It is assumed that a copper film is formed on the surface of the wafer W. With the slurry SL interposed between the copper film formed on the surface of the wafer W and the polishing surface of the polishing pad 22, the surface of the copper film is oxidized by an oxidizing agent and the oxidized copper film surface Is formed by a chelating agent, and the chelating film is removed by the mechanical removal action of the polishing pad 22 and the abrasive grains in the slurry SL, thereby achieving the planarization of copper.

With such a configuration, the same effects as those of the polishing apparatus according to the above-described first embodiment are exhibited, and therefore, a polishing apparatus having a low polishing pressure, a high polishing rate, and a high flattening ability can be realized. .

Second Embodiment An embodiment of a polishing method according to the present invention will be described in a case where the embodiment is applied to a wiring forming process of a semiconductor device by a dual damascene method. The case where copper is used as the wiring material will be described.

First, as shown in FIG. 7A, an interlayer insulating film 102 made of, for example, silicon oxide is formed on a semiconductor substrate 101 made of, for example, silicon, for example, on which an impurity diffusion region (not shown) is appropriately formed. For example, TE as a reaction source
Low pressure CVD using OS (tetraethylorthosilicate)
(Chemical Vapor Deposition) method. The interlayer insulating film is made of a so-called low-dielectric material having a lower dielectric constant than ordinary silicon oxide using TEOS or the like as a raw material.
It can also be formed of k materials. For example, during plasma CVD, carbon fluoride or silicon fluoride is mixed to form FSG (fluorinated silicate glass: SiOF), or by SOG (Spin On Glass) method.
Polyimide polymer film, Teflon polymer film, fluorinated amorphous carbon film, polyarylether polymer film, HSQ (Hydrogen Silsequioxanes: H ₈ Si)
₈ O ₁₂ ), xerogel (porous silica) or the like can be formed as an interlayer insulating film.

Next, as shown in FIG. 7B, a contact hole C leading to the impurity diffusion region of the semiconductor substrate 101 is formed.
The H and the wiring groove M are formed by using, for example, a known photolithography technique and an etching technique. The depth of the wiring groove M is, for example, about 800 nm.

Next, as shown in FIG. 7C, a barrier film 103 is formed on the surface of the interlayer insulating film 102 and in the contact hole C.
H and in the wiring groove M. This barrier film 103
Is, for example, Ta, Ti, W, Co, TaN, TiN,
PVD (Physical Va) using materials such as WN, CoW or CoWP using a sputtering device, a vacuum deposition device, or the like.
The film is formed to a thickness of, for example, about 25 nm by a por deposition method. The barrier film 103 is provided to prevent a material forming a wiring from diffusing into the interlayer insulating film 102 and to improve adhesion to the interlayer insulating film 102. In particular, when the wiring material is copper and the interlayer insulating film 102 is made of silicon oxide as in the present embodiment, copper has a large diffusion coefficient into silicon oxide and is easily oxidized. .

Next, as shown in FIG. 8D, a seed film 104 made of copper of the same material as the wiring forming material is formed on the barrier film 103 by, for example, 150 nm by a known sputtering method.
It is formed with a film thickness of about m. The seed film 104 is formed to promote the growth of copper grains when copper is embedded in the wiring trench M and the contact hole CH.

Next, as shown in FIG. 8E, a wiring layer 105 made of copper is formed on the barrier film 103 so that the contact hole CH and the wiring groove M are buried, for example, as shown in FIG.
It is formed with a thickness of about 600 nm. The wiring layer 105 includes
Preferably, it is formed by an electrolytic plating method or an electroless plating method, but may be formed by a CVD method, a sputtering method, or the like. Note that the seed film 104 is integrated with the wiring layer 105. On the surface of the wiring layer 105, the contact hole CH and the wiring groove M were buried.
For example, irregularities having a height of about 800 nm are formed.

The above process is performed by the same process as the conventional one. Here, a process of removing the extra wiring layer 105 existing on the interlayer insulating film 102 and flattening the same will be described in detail.

First, a complex film having a uniform thickness and a lower mechanical strength than a copper film is formed along the unevenness of the wiring layer 105. In this method of forming a complex film, a slurry containing temperature-controlled abrasive grains, an oxidizing agent, and a ligand is supplied onto the surface of the wafer W. Here, for example, a chelating agent that forms a chelate of copper is used as the ligand. Specifically, quinaldic acid of the chemical structural formula (1), glycine, citric acid, oxalic acid, propionic acid and the like of the chemical structural formula (2) are used. In addition, as the oxidizing agent for copper, for example, aqueous hydrogen peroxide is used, and as the abrasive grains, for example, aluminum oxide (alumina), cerium oxide (ceria), silica, germanium oxide, or the like is used.

[0086]

Embedded image

[0087]

Embedded image NH ₂ CH ₂ COOH (2)

As shown in FIG. 9F, the wiring layer 105 is formed.
Oxide film (Cu (H ₂ O) ₄ ²⁺ ) uniformly on the surface of the copper film by an oxidizing agent such as hydrogen peroxide solution contained in the slurry.
Is formed, and the oxide film is chelated by a chelate reaction (complex formation reaction) with a chelating agent, whereby a chelate film is uniformly formed. The above chelation reaction is promoted by supplying a slurry whose temperature has been adjusted or adjusting the temperature of the wafer. Before being oxidized, the chelation of copper is in a suppressed state.

Here, when quinaldic acid is used as the chelating agent, a film composed of the chelate compound of the chemical structural formula (3) is obtained, and when glycine is used, the film is formed of the chelate compound of the chemical structural formula (4). Film. These chelate films 106 have much lower mechanical strength than copper.

[0090]

Embedded image

[0091]

Embedded image

Next, as shown in FIG.
The protrusions of the chelate film 106 formed on the surface of No. 5 are selectively removed by a mechanical removal action of a polishing tool and abrasive grains contained in the slurry. Since the mechanical strength of the chelate film is extremely small, the chelate film 106 can be easily removed with a small polishing pressure. As described above, the copper film below the chelate film is exposed in the slurry from the projection.

Next, as shown in FIG. 9 (h), the convex portion of the copper film 105 exposed in the slurry is oxidized again by the oxidizing agent, and the oxidized copper is again chelated by the chelating agent. Is done.

Next, as shown in FIG. 10 (i), the convex portions of the chelate film 106 are selectively removed again by mechanical polishing or the like, and the exposed copper film 105 is chelated again. The step of selectively removing the convex portion of
By repeating the process until the excess copper film 105 on the barrier film 103 almost disappears, the copper film 105 is planarized.
Thereafter, the supply of the slurry to the copper film is stopped in order to stop the progress of chelation by the oxidizing agent and the chelating agent in the slurry. The copper film 10
Step 5 of the initial unevenness is alleviated (flattened).

In the copper film flattening and removing step,
Since the polishing is completed on the barrier metal 103, the slurry used is preferably a slurry capable of removing only copper. Specifically, a slurry having a rate selectivity of copper: barrier metal: interlayer insulating film = 1: 0: 0 is preferable. However, even with the slurry prepared for removing the copper film, some of the barrier metal and the interlayer insulating film are removed, and a rate is generated. That is, actually, the rate selection ratio is as follows: copper: barrier metal: interlayer insulating film = 1: 0.5: 0.5. In the polishing method of the present invention, the use of a slurry whose temperature has been adjusted can promote the chelation of copper, thereby increasing the polishing rate of copper. Therefore, the rate selection ratio is set to be copper: barrier metal: interlayer insulating film = 1. : 0: 0.

Next, as shown in FIG. 10 (j), the remaining excess copper film 10 is formed by using a slurry having a rate selectivity of copper: barrier metal: interlayer insulating film = 1: 1: 0.
5 and barrier metal 1 deposited outside the wiring groove
By removing 03, a copper wiring is formed.

According to the method of manufacturing a semiconductor device using the polishing method according to the embodiment of the present invention, for example, the surface of a copper film as a wiring is polished by changing to a complex film such as a chelate film having low mechanical strength. Therefore, it is possible to remove by polishing at a low polishing pressure. Accordingly, damage to the interlayer insulating film below the wiring can be reduced, and the present invention can be applied to a low dielectric constant material having a mechanical strength lower than that of silicon oxide made of TEOS or the like as an insulating film material. Also,
Disadvantages such as dishing and erosion can be prevented. Further, by promoting the above-mentioned complex formation reaction by adjusting the temperature, the generation rate of the chelate film is increased, so that the polishing rate of the copper film can be improved and the throughput of the wafer can be increased. In addition, by adjusting the above operation so that the temperature of the complex formation reaction is constant, the rate of formation of the complex film can be kept almost constant, and as a result, the polishing rate in the wafer is kept constant. Can be done. Therefore, a polishing method having a high leveling ability can be realized.

The present invention is not limited to the above embodiment. For example, the polishing apparatus, the polishing method, and the method for manufacturing a semiconductor device of the present invention can be applied to other metals as well as copper wiring as long as they form a complex having low mechanical strength with a ligand. . Further, the complexing agent is not limited to the chelating agent, but can be changed to various ligands. In addition, various means for promoting the complex formation reaction may be used in addition to the above-described method. For example, a radiation infrared heater or the like may be installed at a position facing the wafer to adjust the surface temperature of the wafer. In addition, various changes can be made without departing from the gist of the present invention.

[0099]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a polishing apparatus according to an embodiment of the present invention;

Under the following conditions, using the polishing apparatus according to the first embodiment of the present invention, planarization polishing of copper was performed using a damascene process.

A slurry containing 10% of aluminum oxide (alumina) in a weakly acidic aqueous solution is used as the slurry abrasive, a stock solution of quinaldic acid is used as the chelating agent, and a hydrogen peroxide solution 35% is used as the oxidizing agent.
% Was used. These abrasive grains, chelating agent and oxidizing agent were mixed at a volume ratio of 1: 0.65: 0.2 to form a slurry. The supply flow rate of the slurry was 300 ml / min.
As the temperature adjustment method, the method described with reference to FIG. 3 of the first embodiment was used. Wheel material is PVA polyvinyl acetal continuous foam, outer shape φ290mm, width 40mm, thickness 20m
m and rotated at 320 rpm. In addition, the rotation speed of the wafer was set to 60 rpm, and the processing torque was set to 3.0 Nm. Note that pure water was supplied to the chuck surface of the wafer table once every two minutes for 10 seconds (70 ° C., 400 ml / mn) as a pre-polishing stage, and the temperature was adjusted in advance.

First Embodiment FIG. 11 shows that a wafer having a copper film having an initial film thickness of 2000 nm under the above conditions was subjected to room temperature (23.degree. C.), 60.degree.
The measurement result of the polishing rate in the case where the copper film is polished by supplying the slurry adjusted to the temperature of ° C. is shown. The horizontal axis indicates the temperature (° C.) of the supplied slurry, and the vertical axis indicates the polishing rate (nm / min) of the copper film. In the measurement, the wafer surface was divided into 21 points in the diameter direction, the film thickness was measured by measuring the sheet resistance at each point, and the polishing rate at each point was calculated by converting the processing time, and the average was calculated. Values were calculated. as a result,
The polishing rate is 208.2 nm / min at room temperature,
397.9 nm / min at 60 ° C and 497.9 at 70 ° C.
It was 5.2 nm / min. Therefore, it can be seen that the polishing rate is increased by 90% at 60 ° C. and 140% at 70 ° C. as the temperature rises, thus realizing a high polishing rate.

Second Embodiment FIG. 12 shows the results of a wafer in-plane uniformity test using a dishing evaluation wafer. The wafer for dishing evaluation has an interlayer insulating film made of silicon oxide formed on each chip of a wafer having a diameter of 8 inches and a width of 10 mm.
Forming a wiring groove having a depth of 800 μm and a depth of 800 nm, forming a barrier metal made of Ta by covering the wiring groove,
Further, a copper film formed with a thickness of 1200 nm on the barrier metal was used. In addition, on the copper film surface of each chip,
There is a step of 800 nm caused by the embedding of the wiring groove. Room temperature (23 ° C) and 7
A slurry adjusted to a temperature of 0 ° C. is supplied to form a copper film of about 10%.
00 nm was polished. In addition, when polishing was performed by supplying slurry at normal temperature, processing was performed for 5 minutes, and when polishing was performed by supplying slurry whose temperature was adjusted to 70 ° C., processing was performed for 2 minutes.

The film thicknesses of the above-mentioned wiring portions on the chip which were present at a total of three places, ie, the central portion A and the end portion C, and the intermediate portion B between the central portion A and the end portion C were measured. In the figure,
Indicates an initial step in each portion, indicates a film thickness of copper in a wiring portion when a slurry at normal temperature is supplied in each portion and polished, and 70 ° C. in each portion.
Shows the film thickness of copper in the wiring portion when the temperature-adjusted slurry is supplied and polished.

As shown in FIG. 12, even when the slurry whose temperature is adjusted to 70 ° C. is supplied and the processing is performed for 2 minutes, the uniformity within the wafer surface is equal to the case where the slurry at normal temperature is supplied and the processing is performed for 5 minutes. Even if the polishing rate is improved, the uniformity in the wafer surface does not decrease due to dishing.
The above result can be said to have a dramatic effect in the case where the polishing rate is simply increased and the dishing is increased in proportion thereto.

Third Embodiment FIG. 13 shows the results of a wafer in-plane uniformity test using a wafer for erosion evaluation. The wafer for erosion evaluation is an interlayer insulating film made of silicon oxide formed on each chip of a wafer having a diameter of 8 inches, and a wiring having a width of 1.5 μm and a thickness of 800 nm on a 1200 μm line of the silicon oxide. A groove is continuously formed at a density of 75%, a barrier metal made of Ta is formed by covering the wiring groove, and a copper film is further
One formed with a thickness of 0 nm was used. A slurry whose temperature was adjusted to room temperature (23 ° C.) and 70 ° C. was supplied to the wafer surface to polish the copper film to about 1000 nm. In addition, when polishing was performed by supplying slurry at normal temperature, processing was performed for 5 minutes, and when polishing was performed by supplying slurry whose temperature was adjusted to 70 ° C., processing was performed for 2 minutes.

The film thicknesses of the above-mentioned wiring portions on the chip which were present at a total of three places, ie, the central portion D and the end portion F, and the intermediate portion E between the central portion D and the end portion F were measured. In the figure,
Indicates an initial step in each portion, indicates a film thickness of copper in a wiring portion when a slurry at normal temperature is supplied in each portion and polished, and 70 ° C. in each portion.
Shows the film thickness of copper in the wiring portion when the temperature-adjusted slurry is supplied and polished.

As shown in FIG. 13, even when the slurry whose temperature is adjusted to 70 ° C. is supplied and the processing is performed for 2 minutes, the uniformity in the wafer surface is equal to that when the slurry at normal temperature is supplied and the processing is performed for 5 minutes. Even if the polishing rate is improved, the uniformity in the wafer surface does not decrease due to the erosion.
This can be said to have a dramatic effect in that conventionally, if the polishing rate is simply increased, the erosion increases in proportion thereto.

Fourth Embodiment FIGS. 14 to 16 show one example of the profile of the dishing evaluation at the central portion A measured in the second embodiment. In each drawing, the horizontal axis indicates the position in the width direction of the copper wiring, and the vertical axis indicates the thickness of the copper film. FIG. 14 shows a wiring width of 100 μm and a step of 800 nm before polishing.
3 shows the thickness distribution of the copper film of FIG. FIG. 15 shows a film thickness distribution when a slurry at normal temperature is supplied to the copper film having the film thickness distribution shown in FIG. 14 and processing is performed for 5 minutes. FIG. 16 shows a film thickness distribution when a slurry whose temperature is adjusted to 70 ° C. is supplied to the copper film having the film thickness distribution shown in FIG. 14 and processing is performed for 2 minutes.

When comparing FIG. 15 and FIG.
Even when the slurry is temperature-adjusted to be processed for 2 minutes, the slurry has the same film thickness distribution as that when the slurry is supplied at room temperature and processed for 5 minutes, thus improving the polishing rate. However, dishing has not increased. This can be said to have a dramatic effect in that conventionally, when the polishing rate is simply increased, the dishing is increased in proportion thereto.

Fifth Embodiment FIGS. 17 to 19 show an example of the profile of the erosion evaluation in the intermediate portion E measured in the third embodiment. In each drawing, the horizontal axis indicates the position in the width direction of the copper wiring, and the vertical axis indicates the thickness of the copper film. FIG. 17 shows that the wiring width is 1.200 μm before the polishing process.
A copper film having a thickness of 1200 nm is formed on a barrier metal in which wiring grooves of 5 μm and a depth of 800 nm are continuously formed at a density of 75%.
The thickness distribution when embedded is shown. FIG. 18 shows a film thickness distribution when a normal temperature slurry is supplied to the copper film having the film thickness distribution shown in FIG. 17 and processing is performed for 5 minutes. FIG.
FIG. 18 illustrates a film thickness distribution when a slurry whose temperature is adjusted to 70 ° C. is supplied to the copper film having the film thickness distribution illustrated in FIG. 17 and processing is performed for 2 minutes.

When comparing FIG. 18 and FIG.
Even when the slurry is temperature-adjusted to be processed for 2 minutes, the slurry has the same film thickness distribution as that when the slurry is supplied at room temperature and processed for 5 minutes, thus improving the polishing rate. However, erosion has not increased. This can be said to have a dramatic effect in that conventionally, if the polishing rate is simply increased, the erosion increases in proportion thereto.

[0113]

According to the polishing apparatus of the present invention, the metal film is changed to a complex having low mechanical strength by a complexing agent, and the copper film is polished at a low polishing pressure. Therefore, disadvantages such as dishing and erosion occur. Flattening processing can be performed without occurrence. Further, the polishing rate can be improved by adjusting the temperature of the complex formation region to a temperature at which the complex formation reaction between the metal film and the complex forming agent is promoted. Furthermore, by making the temperature of the complex formation region constant by the temperature controller, the formation rate of the complex film can be kept constant, and as a result, the polishing rate of the metal film can be kept constant. Therefore, it is possible to realize a polishing apparatus having a high flattening ability while improving a polishing rate.

According to the above-described polishing method of the present invention and the method of manufacturing a semiconductor device using the same, since the surface of the metal film is polished after being changed to a complex film having low mechanical strength, it is polished and removed at a low polishing pressure. It becomes possible. Accordingly, damage to the interlayer insulating film below the wiring can be reduced, and the present invention can be applied to a low dielectric constant material having a mechanical strength lower than that of silicon oxide made of TEOS or the like as an insulating film material. Further, disadvantages such as dishing and erosion can be prevented. Further, by adjusting the temperature of the complex formation region to a temperature that promotes the above-described complex formation reaction, the rate of forming the complex film is increased, so that the polishing rate of the copper film can be improved, and the throughput of the semiconductor device can be improved. Can be raised. In addition, by adjusting the above operation so that the temperature of the complex formation region is constant,
The formation rate of the complex film can be kept almost constant, and as a result, the polishing rate can be kept constant. Therefore, it is possible to realize a polishing method having a high flattening ability while improving a polishing rate.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a polishing apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic enlarged view of a processing head unit.

FIG. 3 is a diagram showing one specific example of a configuration of a slurry supply device 71 and a temperature controller 61.

FIG. 4 is a diagram showing one specific example of a configuration of a slurry supply device 71 and a temperature controller 61.

FIG. 5 is a schematic configuration diagram showing a first modification of the polishing apparatus according to the present invention.

FIG. 6 is a schematic configuration diagram showing a second modification of the polishing apparatus according to the present invention.

FIGS. 7A and 7B are cross-sectional views illustrating a manufacturing process of a method for manufacturing a semiconductor device according to the present invention, wherein FIG. 7A illustrates up to a process of forming an insulating film on a semiconductor substrate, and FIG. (C) shows up to the step of forming a barrier film.

8 shows a step subsequent to that of FIG. 7, wherein (d) shows a step until a copper film as a seed film is formed, and (e) shows a step until a copper film is formed.

9 shows a step subsequent to that of FIG. 8; (f) shows up to a step of forming a complex film on a copper film surface; (g) shows a step up to a step of removing a complex film on a convex portion; The steps up to the step of forming a complex film on the copper film of the convex portion are shown.

FIG. 10 shows a step that follows the step shown in FIG. 9;
Shows the process up to the copper film flattening step, and FIG.

FIG. 11 is a diagram for explaining the first embodiment of the present invention.

FIG. 12 is a diagram for explaining a second embodiment of the present invention.

FIG. 13 is a diagram for explaining a third embodiment of the present invention.

FIG. 14 is a view for explaining a fourth embodiment of the present invention, and shows a film thickness distribution of a copper film before polishing.

FIG. 15 shows a film thickness distribution when the copper film having the film thickness distribution shown in FIG. 14 is processed by supplying a slurry at room temperature.

FIG. 16 is a cross-sectional view of the copper film having the film thickness distribution shown in FIG.
It shows a film thickness distribution when a slurry whose temperature is adjusted to 0 ° C. is supplied and processing is performed.

FIG. 17 is a diagram for explaining a fifth embodiment of the present invention, and shows a film thickness distribution of a copper film before polishing.

FIG. 18 shows a film thickness distribution when the copper film having the film thickness distribution shown in FIG. 17 is processed by supplying a slurry at room temperature.

FIG. 19 is a cross-sectional view of the copper film having the film thickness distribution shown in FIG.
It shows a film thickness distribution when a slurry whose temperature is adjusted to 0 ° C. is supplied and processing is performed.

FIGS. 20A and 20B are cross-sectional views showing a manufacturing process of a method of forming a copper wiring by a dual damascene method according to a conventional example, wherein FIG. (C) shows up to the step of forming a barrier film.

FIG. 21 shows a step that follows the step of FIG. 20;
(D) shows up to a seed film forming step, (e) shows up to a wiring layer forming step, and (f) shows a wiring forming step.

FIGS. 22A and 22B are diagrams for explaining a problem that occurs in a copper film polishing step by a CMP method. FIG. 22A is a cross-sectional view for explaining dishing, and FIG. 22B is a diagram for explaining erosion. And (c) is a cross-sectional view for explaining the recess.

FIG. 23 is a cross-sectional view for explaining scratches and chemical damage generated in a copper film polishing step by a CMP method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Polishing tool holding part, 11 ... Polishing tool, 12 ... Flange member, 13 ... Holding device, 13a ... Spindle, 14 ... Spindle motor, 21a ... Heat insulation material, 22 ... Polishing pad, 24 ... Spindle bearing, 30 ... Z axis Positioning mechanism, 31: Z-axis servo motor, 31a: Ball screw shaft, 32: Z-axis slider, 33: Guide rail, 40: X-axis moving mechanism, 4
1: heater power supply, 42: wafer table, 23a, 4
2a: Heating element, 43: Rotary joint, 44: Drive motor, 45: Holding device, 46: Belt, 47: Processing pan, 48: X-axis slider, 49: X-axis servo motor,
51: Z-axis driver, 52: Spindle driver, 53: Table driver, 54: X-axis driver, 55: Controller, 56: Control panel, 61: Temperature controller, 6
2 thermometer, 71 slurry supply device, 81 pure water supply device, 101 semiconductor substrate, 102 interlayer insulating film, 10
3: barrier film, 104: seed film, 105: copper film, 10
6: chelate film, SC: scratch, CD: chemical damage, SL: slurry, H: pure water.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B24B 57/02 B24B 57/02 H01L 21/3205 H01L 21/88 K 21/768 21/90 C F term ( Reference) 3C047 FF08 GG15 3C058 AA07 AC04 BA08 BC02 CA01 CB01 CB03 DA02 DA12 5F033 HH11 HH15 HH18 HH19 HH21 HH22 HH32 HH33 HH34 JJ01 JJ11 QJ JJ01 RQ11 NN15 NN01 RR21 RR22 RR24 SS04 SS13 XX01 XX17

Claims (38)

[Claims] 1. A polishing apparatus, comprising: a polishing section having a polishing surface, wherein the polishing section contacts the polishing surface of the polishing section with a polishing surface on which a metal film of an object to be polished is formed. In at least the contact area between the surface and the surface to be polished,
A complexing agent supply means for supplying a complexing agent containing a ligand forming a complex of the metal film having a lower mechanical strength than the metal film; and a complexing reaction between the metal film and the complexing agent is promoted. A temperature adjusting means for adjusting the temperature of the complex formation reaction region to a temperature at which the polishing is performed. 2. The polishing apparatus according to claim 1, wherein said complex forming agent contains a chemical polishing agent containing polishing abrasive grains. 3. The polishing apparatus according to claim 1, wherein said metal film is formed of copper. 4. The polishing apparatus according to claim 1, wherein said complex forming agent includes an oxidizing agent which oxidizes said metal film and promotes said complex forming reaction. 5. The polishing apparatus according to claim 1, wherein said complex forming agent supplying means supplies said complex forming agent containing a chelating agent as said ligand. 6. The complex-forming agent according to claim 1, wherein the ligand is at least quinaldic acid, glycine, citric acid, oxalic acid,
The polishing apparatus according to claim 1, wherein the polishing apparatus contains any of propionic acid. 7. The polishing apparatus according to claim 1, wherein said temperature adjusting means adjusts the temperature of said complex forming reaction region by adjusting the temperature of said complex forming agent. 8. The polishing apparatus according to claim 2, wherein said temperature adjusting means adjusts the temperature of said complex forming reaction region by adjusting the temperature of said complex forming agent containing said chemical polishing agent. 9. The polishing apparatus according to claim 1, wherein said temperature adjusting means adjusts the temperature of said complex formation reaction region by adjusting the temperature of said polished surface or said polished surface. 10. The polishing apparatus according to claim 1, further comprising a temperature measuring means for measuring a temperature of said complex formation reaction region. 11. The polishing apparatus according to claim 10, further comprising control means for controlling said temperature adjusting means based on a detection signal from said temperature measuring means so that said temperature value becomes constant. 12. A method for polishing an object to be polished having a metal film on a surface to be polished, wherein a ligand forming a complex of the metal film having lower mechanical strength than the metal film is formed on the surface to be polished. Supplying a complex-forming agent containing the complex-forming agent, forming a complex film on the surface of the metal film with the complex-forming agent, removing the complex film, and exposing the metal film under the removed complex film to the surface. And a step of adjusting the temperature of the complexation reaction region to a temperature at which a complexation reaction between the complexing agent and the metal film is promoted. 13. A step of supplying the complex forming agent to the exposed metal film after the step of removing the complex film, forming the complex film on the surface of the metal film, and removing the complex film. The polishing method according to claim 12, wherein the metal film is polished by repeatedly performing the steps. 14. The polished surface has the metal film having an uneven shape. In the step of forming the complex film, the complex film is formed according to the uneven shape of the metal film. In the step of removing the complex film, the convex portion of the complex film is selectively removed, the metal film of the convex portion is exposed on the surface, and the complex forming agent is supplied again to the exposed metal film of the convex portion. The polishing method according to claim 12, wherein the metal film is planarized and polished by repeating the steps of forming the complex film and removing the complex film. 15. The complex forming agent contains a chemical polishing agent containing abrasive grains, and in the step of removing the complex film, the complex on the surface to be polished by chemical mechanical polishing with the chemical polishing agent. The polishing method according to claim 12, wherein the film is removed. 16. The polishing method according to claim 12, wherein said metal film is formed of copper. 17. The complex forming agent according to claim 12, wherein said complex forming agent includes an oxidizing agent which oxidizes said metal film and promotes said complex forming reaction.
The polishing method as described above. 18. In the step of supplying the complexing agent,
The polishing method according to claim 12, wherein a complex forming agent containing a chelating agent is supplied as the ligand, and in the step of forming the complex film, a chelating film is formed as the complex film. 19. The polishing method according to claim 12, wherein the complex-forming agent contains at least one of quinaldic acid, glycine, citric acid, oxalic acid, and propionic acid as the ligand. 20. The step of supplying the complexing agent,
The polishing method according to claim 12, wherein the temperature of the complex formation reaction region is adjusted by supplying the complex forming agent at a controlled temperature. 21. The step of supplying the complexing agent,
16. The polishing method according to claim 15, wherein the temperature of the complex formation reaction region is adjusted by supplying the complex forming agent containing the chemical abrasive at a controlled temperature. 22. The polishing method according to claim 12, wherein the temperature of the complex formation reaction region is adjusted by adjusting the temperature of the object to be polished. 23. The polishing method according to claim 12, wherein the temperature of the complex formation reaction region is adjusted by adjusting the temperature of a polishing section used in the step of removing the complex film. 24. A step of forming a wiring groove on an insulating film formed on a substrate, and unevenness corresponding to a step of the wiring groove on the entire surface of the insulating film so as to fill the wiring groove. Depositing a metal film having a shape on the surface, supplying a complex-forming agent containing a ligand that forms a complex of the metal film having a lower mechanical strength than the metal film on the surface of the metal film, Forming a complex film of the metal film on the surface of the metal film by using a complexing agent; and selectively removing a convex portion of the complex film according to the uneven shape of the metal film, and forming the complex film under the complex film. Exposing the metal film to the surface, and adjusting the temperature of the complex formation reaction region to a temperature at which the complex formation reaction between the complex forming agent and the metal film is promoted. 25. After the step of removing the complex film, the complex forming agent is supplied to the exposed surface of the metal film to form the complex film on the surface of the metal film, and the complex film is removed. The method of manufacturing a semiconductor device according to claim 24, wherein the metal film is polished by repeating the steps. 26. In the step of depositing the metal film,
The method for manufacturing a semiconductor device according to claim 24, wherein a copper film is deposited. 27. A step of forming a conductive barrier film by covering the insulating film and the inside of the wiring groove after the step of forming the wiring groove and before the step of depositing the copper film. 27. The method of manufacturing a semiconductor device according to claim 26, further comprising: depositing the copper film on the barrier film so as to fill the wiring groove in the step of depositing the copper film. 28. The step of supplying the complexing agent,
3. The method according to claim 2, further comprising: supplying the complex forming agent containing a chemical abrasive containing abrasive grains, and removing the complex film by chemical mechanical polishing with the chemical abrasive in the step of removing the complex film.
5. The method for manufacturing a semiconductor device according to item 4. 29. The complexing agent includes an oxidizing agent that oxidizes the metal film and promotes the complexing reaction.
The manufacturing method of the semiconductor device described in the above. 30. The step of supplying the complexing agent,
25. The method of manufacturing a semiconductor device according to claim 24, wherein a complex forming agent containing a chelating agent is supplied as the ligand, and in the step of forming the complex film, a chelating film is formed as the complex film. 31. The method according to claim 24, wherein at least one of quinaldic acid, glycine, citric acid, oxalic acid, and propionic acid is used as the ligand contained in the complex forming agent. 32. The step of supplying the complexing agent,
25. The method of manufacturing a semiconductor device according to claim 24, wherein the temperature of the complex forming reaction region is adjusted by supplying the complex forming agent at a controlled temperature. 33. The step of supplying the complexing agent,
29. The method of manufacturing a semiconductor device according to claim 28, wherein the temperature of the complex formation reaction region is adjusted by supplying the complex forming agent containing the chemical polishing agent at a controlled temperature. 34. The method of manufacturing a semiconductor device according to claim 24, wherein the temperature of the complex formation reaction region is adjusted by adjusting the temperature of the substrate on which the metal film is formed. 35. The polishing method according to claim 24, wherein the temperature of the complex formation reaction region is adjusted by adjusting the temperature of a polishing section used in the step of removing the complex film. 36. In the step of forming the barrier film,
As a material for forming the barrier film, at least Ta, T
i, W, Co, TaN, TiN, WN, CoW or C
The method of manufacturing a semiconductor device according to claim 27, wherein the barrier film is formed using any one of oWP. 37. In the step of forming the wiring groove,
Along with the formation of the wiring groove, a contact hole for connecting an impurity diffusion layer or a wiring formed under the insulating film and a wiring formed in the wiring groove is formed, and the metal film is deposited. 25. The method of manufacturing a semiconductor device according to claim 24, wherein said metal is buried in said contact hole together with said wiring groove. 38. The insulating film is formed of at least silicon oxide, fluorinated silicate glass, polyimide polymer compound, Teflon polymer compound, fluorinated amorphous carbon compound, polyaryl ether polymer compound, HSQ, xerogel. 25. The method of manufacturing a semiconductor device according to claim 24, wherein the method is formed of a material containing any of them.