KR101088785B1 - Polishing apparatus and polishing method - Google Patents

Abstract

The polishing apparatus according to the present invention can supply the polishing liquid to the surface to be polished of the workpiece uniformly and efficiently. The polishing apparatus includes a polishing table 22 having a polishing surface, and a top ring 24 for holding the workpiece to be polished to press the workpiece against the polishing surface. The polishing apparatus also distributes the polishing liquid evenly over the entire surface of the workpiece by a polishing liquid supply port 57 for supplying a polishing liquid to the polishing surface, and by relative movement of the workpiece and the polishing surface. In order to move the polishing liquid supply port to include.

Description

Polishing Apparatus and Polishing Method {POLISHING APPARATUS AND POLISHING METHOD}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and a polishing method, and more particularly, to a polishing apparatus and a polishing method for polishing a workpiece such as a semiconductor wafer with a flat finish.

The present invention also relates to a method of forming interconnects, and more particularly, to a method of forming interconnects for forming interconnects in the form of conductive films on a substrate such as a semiconductor wafer.

In recent years, as semiconductor device integration processes become faster, wiring patterns or interconnects become more fine, and distances between interconnects connecting active areas become smaller. The photolithography process can form interconnects having a line width of 0.5 μm or less, but because the depth of focus of the optical system is relatively small, the surfaces on which the pattern images are to be focused by the stepper are required to be as flat as possible. Therefore, in photolithography, it is essential to make the surface of the semiconductor wafer flat. One way to planarize the surfaces of semiconductor wafers is to polish them using a polishing apparatus, and this process is called chemical mechanical polishing (CMP).

The chemical-mechanical polishing (CMP) apparatus has a polishing table with a polishing pad disposed on the top surface and a top ring positioned on the polishing pad. The semiconductor wafer to be polished is positioned between the polishing pad and the top ring and supported by the top ring. While the polishing liquid or slurry is supplied to the surface of the polishing pad, the top ring presses the semiconductor wafer against the polishing pad and rotates the semiconductor wafer relative to the polishing pad, thereby polishing the surface of the semiconductor wafer to a planar finish. .

Known chemical-mechanical polishing apparatuses of the above-mentioned attributes are disclosed in, for example, Japanese Patent Laid-Open No. 2002-113653, Japanese Patent Laid-Open No. H10-58309, Japanese Patent Laid-Open No. H10-286758, Japanese Patent Laid-Open No. 2003- 133277 and Japanese Patent Laid-Open No. 2001-237208.

It is a first object of the present invention to provide a polishing apparatus capable of uniformly and efficiently supplying a polishing liquid to a surface to be polished of a workpiece.

A second object of the present invention is to provide a polishing apparatus capable of stably supplying a polishing liquid between a polishing surface and a workpiece to be polished.

The third object of the present invention is to maintain a uniform polishing liquid film on the polishing surface by maintaining an appropriate amount of polishing liquid on the polishing surface even under a condition where the polishing pressure on the polishing surface is low and the relative speed between the polishing surface and the workpiece is high. It is to provide a polishing apparatus that can be formed.

A fourth object of the present invention is to provide a polishing apparatus capable of increasing the working efficiency of a polishing liquid by increasing the amount of the polishing liquid held on the polishing surface.

A fifth object of the present invention is to provide a polishing apparatus and a polishing method capable of keeping the polishing surface clean at all times in order to stabilize the polishing characteristics of the polishing surface.

A sixth object of the present invention is to provide a polishing method which can effectively rinse and remove residues such as a polishing liquid attached to a surface to be polished after the workpiece is polished in the main polishing process.

A seventh object of the present invention is to provide a polishing method which can prevent the preceding polishing step from overloading the subsequent polishing step in the multi-step polishing process.

An eighth object of the present invention is to provide an interconnect formation method capable of forming interconnects without generating defects therein.

According to the first embodiment of the present invention, there is provided a polishing apparatus capable of uniformly and efficiently supplying a polishing liquid to the surface to be polished of a workpiece. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface. The polishing apparatus further includes a polishing liquid supply port for supplying a polishing liquid to the polishing surface, and by the relative motion of the workpiece and the polishing surface, to uniformly distribute the polishing liquid over the entire surface of the workpiece. And a moving mechanism for moving the polishing liquid supply port.

The polishing liquid can be uniformly and efficiently supplied to the surface to be polished of the workpiece by moving the polishing liquid supply port while the workpiece is polished. Specifically, since the polishing liquid supplied to the surface to be polished of the workpiece is uniformly distributed, the polishing rate of the workpiece is improved, and the in-plane uniformity of the polishing rate is improved. As the polishing liquid is efficiently supplied, the amount of polishing liquid used is reduced, and wasteful consumption of any polishing liquid is reduced, thereby lowering the polishing cost.

According to the second embodiment of the present invention, there is provided a polishing apparatus capable of uniformly and efficiently supplying a polishing liquid to a surface to be polished of a workpiece. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface. The polishing apparatus is also configured to uniformly distribute the polishing liquid over the entire surface of the workpiece by a plurality of polishing liquid supply ports for supplying a polishing liquid to the polishing surface, and by relative movement of the workpiece and the polishing surface. And a liquid speed control mechanism for controlling the ratio of the polishing liquid supplied from the polishing liquid supply ports.

The polishing liquid can be uniformly and efficiently supplied to the surface to be polished of the workpiece by controlling the ratio of the polishing liquid supplied from the polishing liquid supply port. Specifically, since the polishing liquid supplied to the surface to be polished of the workpiece is uniformly distributed, the polishing rate of the workpiece is improved, and the in-plane uniformity of the polishing rate is improved. As the polishing liquid is efficiently supplied, the amount of polishing liquid used is reduced, and wasteful consumption of any polishing liquid is reduced, thereby lowering the polishing cost.

According to the third embodiment of the present invention, there is provided a polishing apparatus capable of uniformly and efficiently supplying a polishing liquid to a surface to be polished of a workpiece. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface. The polishing apparatus also includes a dispensing apparatus for dispensing and supplying a polishing liquid to the polishing surface, and a polishing liquid supply port for supplying the polishing liquid to the dispensing apparatus.

Since the polishing liquid from the polishing liquid supply port is distributed and supplied to the polishing surface, the polishing liquid supplied to the surface to be polished of the workpiece is uniformly distributed. Therefore, the polishing rate of the workpiece is improved, and the in-plane uniformity of the polishing rate is improved.

According to the fourth embodiment of the present invention, a polishing apparatus capable of uniformly and efficiently supplying a polishing liquid to a surface to be polished of a workpiece is provided. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface. The polishing apparatus also distributes a polishing liquid supply port for supplying a polishing liquid to the polishing surface, and a polishing liquid supplied from the polishing liquid supply port, thereby supplying the dispensed polishing liquid between the workpiece and the polishing surface. And a dispensing device for

Since the polishing liquid supplied from the polishing liquid supply port can be dispensed by the dispensing apparatus, the polishing liquid supplied to the surface to be polished of the workpiece is evenly distributed. Therefore, the polishing rate of the workpiece is improved, and the in-plane uniformity of the polishing rate is improved.

According to the fifth embodiment of the present invention, there is provided a polishing apparatus capable of stably supplying a polishing liquid between a polishing surface and a workpiece to be polished. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface. The top ring has a retaining ring for holding an outer circumferential edge of the workpiece. The retaining ring which comes into contact with the polishing surface has a groove formed in the surface thereof, the groove extending between the outer circumferential surface and the inner circumferential surface of the retainer ring. The groove has an opening ratio in the range of 10% to 50% at the outer circumferential surface of the retaining ring.

The groove formed between the outer circumferential surface and the inner circumferential surface of the retainer ring and formed in the retainer ring may stably supply the polishing liquid between the polishing surface and the workpiece. According to the opening ratio of the groove in the range of 10% to 50% on the outer circumferential surface of the retaining ring, since the polishing liquid can be effectively supplied between the polishing surface and the workpiece, a stable polishing rate is achieved and any after reaction An inert polishing liquid can be effectively discharged out of the retaining ring through the groove.

According to the sixth embodiment of the present invention, even if the polishing pressure on the polishing surface is low and the relative speed between the polishing surface and the workpiece is high, an appropriate amount of polishing liquid is maintained on the polishing surface to make it uniform on the polishing surface. There is provided a polishing apparatus capable of forming a polishing liquid film. The polishing apparatus includes a polishing table having a polishing surface, and a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface. The polishing apparatus also includes a polishing liquid supply port for supplying a polishing liquid to the polishing surface, and a relative moving mechanism for moving the polishing surface and the workpiece at a relative speed of 2 m / s or more. The polishing surface has grooves having a cross-sectional area of at least 0.38 mm ² .

As grooves having a wide cross-sectional area are formed in the polishing surface, an appropriate amount of polishing liquid is maintained on the polishing surface even under conditions where the polishing pressure on the polishing surface is low and the relative speed between the polishing surface and the workpiece is high. A uniform polishing liquid film can be formed.

According to the seventh embodiment of the present invention, there is provided a polishing apparatus capable of increasing the working efficiency of the polishing liquid by increasing the amount of the polishing liquid held on the polishing surface. The polishing apparatus includes a polishing table having a polishing surface, a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface, and a polishing liquid supply port for supplying a polishing liquid to the polishing surface. do. The polishing surface has a plurality of holes formed therein having an open area of 2.98 mm ² or more.

Since a plurality of holes each having a large open area is formed in the polishing surface, the amount of polishing liquid held on the polishing surface is increased, and the working efficiency of the polishing liquid is improved. Therefore, the amount of polishing liquid used is reduced, and the polishing cost is reduced.

According to the eighth embodiment of the present invention, there is provided a polishing apparatus capable of uniformly supplying a polishing liquid to a surface to be polished of a workpiece. The polishing apparatus includes a polishing table having a polishing surface, and a plurality of polishing liquid supply ports for supplying a polishing liquid to the polishing surface. The polishing apparatus also includes a plurality of polishing liquid supply lines respectively extending from the polishing liquid supply ports and directly connected to a polishing liquid circulation system disposed outside the polishing apparatus.

According to this aspect, the workpiece can be uniformly supplied with the polishing liquid. Therefore, the polishing rate of the workpiece is improved, and the in-plane uniformity of the polishing rate is improved.

According to the ninth embodiment of the present invention, there is provided a polishing apparatus capable of keeping the polishing surface clean at all times in order to stabilize the polishing characteristics of the polishing surface. The polishing apparatus includes a polishing table having a polishing surface, a top ring for holding the workpiece to be polished to press the workpiece against the polishing surface, and a fluid spray for spraying a mixed fluid of a cleaning liquid and a gas onto the polishing surface. Includes an appliance. The polishing apparatus also includes a discharge mechanism for discharging the mixed fluid from the polishing surface, wherein the discharge mechanism is disposed downstream of the fluid injection mechanism with respect to the direction in which the polishing surface moves.

The discharge mechanism can immediately discharge the cleaning liquid from the fluid spray mechanism out of the polishing surface, thereby keeping the polishing surface clean at all times. Therefore, the polishing characteristics of the polishing apparatus can be stabilized, and the fluid ejection mechanism can be made to perform in-situ atomizing while the workpiece is being polished.

According to the tenth embodiment of the present invention, there is provided a polishing method capable of keeping the polishing surface clean at all times in order to stabilize the polishing characteristics of the polishing surface. According to the polishing method, the polishing surface and the workpiece are moved relative to each other so that the workpiece is pressed and polished against the polishing surface of the polishing table. The mixed fluid of the cleaning liquid and the gas is injected from the fluid spray mechanism to the polishing surface while the workpiece is polished. The mixed fluid is discharged from the polishing surface by a discharge mechanism disposed downstream of the fluid injection mechanism with respect to the direction in which the polishing surface moves.

In the above polishing method, the discharge mechanism can immediately discharge the cleaning liquid from the fluid injection mechanism, away from the polishing surface, thereby keeping the polishing surface clean at all times. Therefore, the polishing characteristics of the polishing apparatus can be stabilized, and the fluid ejection mechanism can perform in-situ atomization while the workpiece is being polished.

According to an eleventh embodiment of the present invention, after a workpiece is polished in the main polishing process, a polishing method is provided which can effectively wash off and remove residues such as a polishing liquid attached to the surface to be polished of the workpiece. According to the polishing method, the workpiece is polished under a low pressure of 13.79 kPa or less, and then, while supplying water to the workpiece, the workpiece under a low pressure of 13.79 kPa or less at a relative speed of 2 m / s or more between the workpiece and the polishing surface. Polish

According to the polishing method, after the workpiece is polished under low pressure, residues such as a polishing liquid attached to the surface to be polished of the workpiece can be effectively washed off and removed.

According to a twelfth embodiment of the present invention, after a workpiece is polished in the main polishing process, a polishing method is provided which can effectively wash off and remove residues such as a polishing liquid attached to the surface to be polished of the workpiece. According to the polishing method, the workpiece is polished under a low pressure of 13.79 kPa or less, and then, while supplying a chemical solution to the workpiece, the workpiece is subjected to a low pressure of 13.79 kPa or less at a relative speed of 2 m / s or more between the workpiece and the polishing surface. Polish the workpiece.

According to the polishing method, after the workpiece is polished under low pressure, residues such as a polishing liquid attached to the surface to be polished of the workpiece can be effectively washed off and removed.

According to a thirteenth embodiment of the present invention, a polishing method is provided in which a preceding polishing step in a multistage polishing process, in particular a two-stage polishing process, can be prevented from excessively burdening subsequent polishing steps. The polishing method includes polishing the workpiece to remove a substantial portion of the first film formed on the workpiece from the first stage, and leaving the interconnect area, until the second film on the workpiece is exposed at the second stage. And polishing the workpiece to remove remaining portions of the first film. The polishing method may further include presetting a film thickness distribution for the first film when transitioning from the first stage polishing to the second stage polishing, to obtain a film thickness distribution of the first film, to polish the first stage. Measuring the thickness of the first film by using a vortex sensor, and in order to make the obtained film thickness distribution of the first film equal to the film thickness distribution preset for the first film, polishing conditions in the second stage polishing. Adjusting them.

The polishing method makes it possible to reliably achieve the desired film thickness distribution while monitoring the actual film thickness distribution. Since the first stage polishing can always be switched to the second stage polishing at the desired film thickness distribution, the first stage polishing is prevented from over burdening the second stage polishing. Furthermore, the polishing method can prevent dishing and corrosion from occurring after the second stage polishing, and can reduce the time period consumed by the second stage polishing, so that the productivity is improved and the polishing cost is reduced. do.

According to a fourteenth embodiment of the present invention, there is provided an interconnect forming method capable of forming an interconnect without causing a defect therein. The interconnect forming method includes forming a flat conductive thin film on the substrate, and removing the flat conductive thin film from the substrate by a chemical etching process.

After the flat conductive thin film is formed on the substrate, the conductive thin film is removed by a chemical etching process that has no mechanical action and does not require electrical connection.

According to the first to fourth embodiments of the present invention, the polishing liquid can be supplied uniformly and efficiently to the surface to be polished of the workpiece.

According to the fifth embodiment of the present invention, the polishing liquid can be stably supplied between the polishing surface and the workpiece.

According to the sixth embodiment of the present invention, even under conditions in which the polishing pressure on the polishing surface is low and the relative speed between the polishing surface and the workpiece is high, an appropriate amount of polishing liquid is maintained on the polishing surface to make it uniform on the polishing surface. One polishing liquid film can be formed.

According to the seventh embodiment of the present invention, the amount of the polishing liquid held on the polishing surface is increased, so that the working efficiency of the polishing liquid can be increased.

According to the eighth embodiment of the present invention, the polishing liquid can be uniformly supplied to the workpiece.

According to the ninth and tenth embodiments of the present invention, the polishing surface is always kept clean to stabilize the polishing characteristics of the polishing surface.

According to the eleventh and twelfth embodiments of the present invention, after the workpiece is polished in the main polishing process, residues such as a polishing liquid attached to the surface to be polished of the workpiece can be effectively washed out and removed.

According to the thirteenth embodiment of the present invention, in the multi-step polishing process, the preceding polishing step does not place excessive burden on subsequent polishing steps.

According to the fourteenth embodiment of the present invention, interconnects can be formed without a defect occurring therein.

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description when read in conjunction with the accompanying drawings illustrating preferred embodiments of the present invention by way of example.

1 is a plan view of a polishing apparatus according to an embodiment of the present invention;

FIG. 2 is a vertical sectional view of a portion of the polishing unit of the polishing apparatus shown in FIG. 1; FIG.

3 is a bottom view of the retainer ring of the top ring shown in FIG. 2;

4 is a bottom view of another retainer ring for use with the top ring shown in FIG. 2;

5 is a bottom view of another retainer ring for use with the top ring shown in FIG. 2;

FIG. 6 is a bottom view of another retainer ring for use with the top ring shown in FIG. 2; FIG.

7 is a schematic plan view of the polishing unit of the polishing apparatus shown in FIG. 1;

8 is a perspective view of a gas injection mechanism used in the polishing unit shown in FIG.

9 is a plan view of a modified polishing unit for use in the polishing apparatus shown in FIG. 1;

FIG. 10 is a perspective view of a polishing pad of the polishing unit shown in FIG. 7; FIG.

FIG. 11 is an enlarged vertical sectional view of the polishing pad shown in FIG. 10; FIG.

12 is an enlarged plan view of a modification of the polishing pad shown in FIG. 10;

13 is a plan view of a modification of the polishing unit of the polishing apparatus shown in FIG. 1;

14 is a plan view of another modification of the polishing unit of the polishing apparatus shown in FIG. 1;

FIG. 15 is a plan view of another modification of the polishing unit of the polishing apparatus shown in FIG. 1; FIG.

FIG. 16 is a plan view of another modification of the polishing unit of the polishing apparatus shown in FIG. 1; FIG.

FIG. 17 is a plan view of another modification of the polishing unit of the polishing apparatus shown in FIG. 1; FIG.

18 is a plan view of another modification of the polishing unit of the polishing apparatus shown in FIG. 1;

19 is a plan view of another modification of the polishing unit of the polishing apparatus shown in FIG. 1;

20 is a plan view of another modification of the polishing unit of the polishing apparatus shown in FIG. 1;

FIG. 21 is a perspective view of a modified polishing liquid supply nozzle for use in the polishing unit of the polishing apparatus shown in FIG. 1; FIG.

FIG. 22 is a vertical sectional view of the polishing liquid supply nozzle shown in FIG. 21; FIG.

FIG. 23 is a perspective view of a modification of the polishing liquid supply nozzle shown in FIG. 21; FIG.

24 is a perspective view of another modified polishing liquid supply nozzle for use in the polishing unit of the polishing apparatus shown in FIG. 1;

25 is a perspective view of another modification of the polishing liquid supply nozzle shown in FIG. 21;

FIG. 26 is a perspective view of another modified polishing liquid supply nozzle for use in the polishing unit of the polishing apparatus shown in FIG. 1; FIG.

FIG. 27 is a plan view of another modified polishing liquid supply nozzle for use in the polishing unit of the polishing apparatus shown in FIG. 1; FIG.

28 is a schematic view of another modified polishing liquid supply nozzle for use in the polishing unit of the polishing apparatus shown in FIG.

29 is a schematic diagram of a polishing liquid supply system of a conventional polishing apparatus;

30 is a schematic view of a polishing liquid supply system according to the present invention;

31A and 31B are schematic views of a fluid pressure valve for use in the polishing liquid supply system shown in FIG. 30;

32 is a vertical sectional view of a modification of the top ring shown in FIG. 2;

33A-33C are cross-sectional views illustrating a CMP process to planarize a copper damascene interconnect;

34A is a cross sectional view of an overpolished workpiece and FIG. 34B is a cross sectional view of an underpolished workpiece;

35 is a plan view of a polishing apparatus for polishing a semiconductor wafer with a swingable polishing liquid supply nozzle;

FIG. 36A is a graph showing the polishing speed of the semiconductor wafer polished by the polishing apparatus shown in FIG. 35 when the polishing liquid supply nozzle is swinging, and FIG. 36B is a graph showing the polishing rate when the polishing liquid supply nozzle is not swinging. A graph showing a polishing rate of the semiconductor wafer polished by the polishing apparatus shown; And

FIG. 37 shows the polishing liquid supplied from one polishing liquid supply port (single), while supplying the polishing liquid from the plurality of polishing liquid supply ports (multi), as compared with the removal rate of the semiconductor wafer polished by the polishing apparatus. It is a graph showing the removal rate of the semiconductor wafer polished by the polishing apparatus shown in FIG.

Hereinafter, a polishing apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same or corresponding reference numerals throughout the drawings and will not be repeated.

1 shows a plan view of a polishing apparatus according to an embodiment of the present invention. As shown in Fig. 1, the polishing apparatus includes three wafer cassette arrays 10 detachably mounted on an end wall thereof to hold a semiconductor wafer, and a moving mechanism disposed along the wafer cassette array 10. (12) is provided. A first transfer robot 24 is mounted on the moving mechanism 12 and has two hands for selectively accessing the wafer cassette 10.

The polishing apparatus has four polishing unit arrays 20 arranged in the longitudinal direction thereof. Each polishing unit 20 includes a polishing table 22 having a polishing surface, a top ring 24 for holding and pressing a semiconductor wafer against the polishing surface of the polishing table 22 for polishing the semiconductor wafer. A polishing liquid supply nozzle 26 for supplying a liquid and a dressing liquid (for example, water) to the polishing table 22, a dresser 28 for dressing the polishing table 22, and a liquid (for example, pure water); And a spraying device 30 for atomizing a mixed fluid consisting of gas (eg nitrogen) to spray the atomized fluid from one or more nozzles to the polishing surface.

The first linear transport device 32 and the second linear transport device 34 are disposed vertically along the polishing unit 20 to transport semiconductor wafers along the polishing unit array 20 in the longitudinal direction of the polishing device. do. An inversion machine 36 for inverting the semiconductor wafer received from the first transfer robot 14 is disposed at one end of the first linear transport apparatus 32 closer to the wafer cassette 10.

The polishing apparatus also includes a second transfer robot 38, an inversion machine 40 for overturning the semiconductor wafer received from the second transfer robot 38, and four cleaning machine arrays 42 for cleaning the polished semiconductor wafer. And a transfer unit 44 for transferring semiconductor wafers between the reversing machine 40 and the cleaning machine 42. The second transfer robot 38, the reversing machine 40, and the cleaning machine 42 are arranged linearly on one side thereof in the longitudinal direction of the polishing apparatus.

The semiconductor wafers housed in the wafer cassette 10 are introduced into each polishing unit 20 through the reversing machine 36, the first linear transport device 32, and the second linear transport device 34. The semiconductor wafer is polished in each polishing unit 20. The polished semiconductor wafers are then introduced into the cleaning machine 42 through the second transfer robot 38 and the reversing machine 40 and cleaned by each cleaning machine 42. The cleaned semiconductor wafers are then transferred back to the wafer cassette 10 by the first transfer robot 14.

2 shows a vertical sectional view of a portion of each polishing unit 20. As shown in FIG. 2, the polishing table 22 of the polishing unit 20 is connected to the motor 50 disposed thereunder, and rotates about its own axis in the direction indicated by the arrow. A polishing pad 52 having an upper polishing surface is provided on the upper surface of the polishing table 22. The top ring 24 is coupled to the lower end of the vertical top ring shaft 54. A retainer ring 56 for holding the outer edge of the semiconductor wafer W is mounted on the outer peripheral portion of the lower portion of the top ring 24.

The top ring shaft 54 is coupled to a motor (not shown) at its upper end and also to a lifting cylinder (not shown). Therefore, the top ring 24 is movable and rotatable in a vertical direction about its own axis as indicated by the arrow to press the semiconductor wafer W against the polishing pad 52 under the desired pressure, thereby The semiconductor wafer W is rotated with respect to the polishing pad 52.

In operation of the polishing unit 20, the semiconductor wafer W is held on the lower surface of the top ring 24 and is polished by a lifting cylinder on the polishing table 22 which is being rotated by the motor 50. 52). The polishing liquid Q is supplied onto the polishing pad 52 from the polishing liquid supply port 57 of the polishing liquid supply nozzle 26. Then, the semiconductor wafer W is polished with the polishing liquid Q existing between the polishing pad 52 and the lower surface to be polished of the semiconductor wafer W.

As shown in FIG. 2, an eddy current sensor 58 for measuring the film thickness of the semiconductor wafer W is embedded in the polishing table 22. The wire 60 extends from the eddy current sensor 58 through the support shaft 62 and the polishing table 22 connected to the lower end thereof, and is a rotary connector (or slip ring) mounted on the lower end of the support shaft 62. 64 is connected to the control unit 66. While the vortex sensor 58 is moving below the semiconductor wafer W, the vortex sensor 58 is continuously below the semiconductor wafer W along the path of the vortex sensor 58 on the surface of the semiconductor wafer W. The thickness of a conductive film such as a copper film formed on the surface is detected.

In order to meet the requirements for faster semiconductor devices, it has been studied to make insulating films between interconnects in semiconductor devices of lower dielectric constant materials, such as low-k materials. Materials with lower dielectric constants, such as low-k materials, are porous and mechanically brittle, so, for example, in polishing processes of copper damascene interconnects of low-k materials, to levels below 13.79 kPa (2 psi). It is desired to minimize the pressure (polishing pressure) applied to the semiconductor wafer being polished.

In general, however, the polishing rate in the polishing process depends on the polishing pressure and decreases as the polishing pressure is lowered. Therefore, in order to polish the copper film, a polishing liquid having a stronger chemical effect may be used to compensate for the decrease in the polishing pressure. If a polishing liquid with stronger chemical action is used, uniform and stable polishing characteristics cannot be achieved unless a more stable chemical reaction occurs between the polishing liquid and the copper film. As a result, in the polishing process, it is preferable to use a polishing liquid having a stronger chemical action in order to stably supply an unreacted polishing liquid between the polishing pad and the semiconductor wafer.

According to this embodiment, the retainer ring 56 of the top ring 24 has a groove formed therein to more stably supply the polishing liquid between the polishing pad 52 and the semiconductor wafer W. 3 is a bottom view of the retainer ring 56 shown in FIG. 2. As shown in FIG. 3, the retainer ring 56 has a plurality of grooves 74 formed on the bottom surface at equal circumferential intervals and extending between the outer circumferential surface 70 and the inner circumferential surface 72. . In FIG. 3, the top ring 24 rotates clockwise, and each groove 74 rotates the outer circumferential opening 76 located in front of the inner circumferential opening 78, that is, the top ring 24 rotates. In the direction. The groove 74 formed in the retainer ring 56 is effective for efficiently and stably supplying the polishing liquid between the polishing pad 52 and the semiconductor wafer W located inside the retainer ring 56.

The outer circumference opening 76 of the groove 74 has an open percentage in the range of about 10% to 50% with respect to the surface area of the outer circumferential surface 70, depending on the strength of the chemical action of the polishing liquid. For example, when a predetermined polishing liquid is used, if the opening percentage of the outer circumferential opening 76 is 0%, the polishing liquid cannot be sufficiently supplied between the polishing pad 52 and the semiconductor wafer W. The polishing rate will not be obtained. On the other hand, if the opening percentage of the outer circumference opening 76 is excessively high, for example, exceeding 50%, the polishing liquid having passed through the predetermined groove 74 radially inwardly of the retaining ring 56 may be filled with other grooves ( 74, it flows out, so that it cannot be effectively held between the polishing pad 52 and the semiconductor wafer (W). If the open percentage of the outer circumference opening 76 is selected in the range of about 10% to 50%, the polishing liquid can be effectively supplied between the polishing pad 52 and the semiconductor wafer W for a stable polishing rate. The open percentage of the outer circumference 76 selected in the range of approximately 10% to 50% allows the inert polishing liquid after the reaction to be effectively discharged to the outside of the retainer ring 56 through the groove 74. The dimensions of the grooves 74 and the pitch between the grooves 74 are determined in accordance with the opening percentage of the outer circumference opening 76.

If the top ring 24 rotates counterclockwise when viewed from its bottom, the groove 74 must be oriented in a direction opposite to the groove 74 shown in FIG. 3, as shown in FIG. . Alternatively, as shown in FIG. 5, the grooves 74 are radially disposed at equally spaced circumferential intervals such that the grooves 74 are irrespective of the direction in which the top ring 24 can rotate. May be used. As shown in FIG. 6, the radial groove 74 may have an inner circumferential opening 78 that is larger than its outer circumferential opening 76.

In order to make the groove 74 of the retainer ring 56 more effective, the rotation speed of the top ring 24 is less than or equal to the rotation speed of the polishing table 22, more preferably approximately the rotation speed of the polishing table 22. It should be about 1/3 to 1 / 1.5. The polishing table 22 and the top ring 24 may be rotated in one direction or in the opposite direction. If the rotational speeds of the polishing table 22 and the top ring 24 are set to the relative values, the polishing apparatus can polish the semiconductor wafer W more uniformly.

Specifically, if the rotational speed of the top ring 24 is faster than the rotational speed of the polishing table 22, the retainer ring 56 located on the outer circumferential surface of the top ring 24 is the polishing pad 52 and the semiconductor wafer ( There is a tendency to disturb the inflow of the polishing liquid between W), which prevents the polishing liquid from being fed efficiently. If the rotation speed of the top ring 24 is less than or equal to the rotation speed of the polishing table 22, the polishing liquid can be efficiently supplied through the groove 74 between the polishing pad 52 and the semiconductor wafer W, so that the polishing apparatus Polishes the semiconductor wafer W more uniformly.

FIG. 7 shows a schematic plan view of each polishing unit 20 of the polishing apparatus shown in FIG. 1. As shown in FIG. 7, the spraying device 30 is arranged upstream of the top ring 24 with respect to the direction in which the polishing table 22 rotates. The spray device 30 functions as a fluid spray mechanism for injecting a mixed fluid consisting of a cleaning liquid and a gas into the polishing pad 52. For example, a mixed fluid consisting of nitrogen gas and pure water or chemical liquid is injected from the spray device 30 to the polishing pad 52. The mixed fluid is sprayed as 1) fine liquid particles, 2) fine solid liquid particles or 3) liquid-vaporizing gas particles (which may be referred to as "fog or spray" states).

When a mist or sprayed mixed fluid is injected into the polishing pad 52, any polishing liquid and swamp trapped in a recess in the polishing pad 52 are lifted therefrom by the gas contained in the mixed fluid. And washed with a cleaning liquid such as pure water, chemical liquid and the like. In this way, any polishing liquid and swamp that may be present on the polishing pad 52 and may scratch the semiconductor wafer W can be effectively removed.

After the semiconductor wafer is polished by the CMP process, a polishing residue (copper complex in the case where the copper film is polished) containing the remaining abrasive grains and the warp is generally present on the polishing surface of the semiconductor wafer. If these polishing residues are not removed, the polishing surface of the semiconductor wafer may be damaged or the chemical reaction of the polishing liquid may be inhibited in a subsequent polishing process, thereby making it easy to reduce the polishing rate. Therefore, it is desirable that there is no or little polishing residue on the polished surface of the semiconductor wafer. According to a normal CMP process, at the interval between polishing cycles, dressing of the polishing surface is performed by the dresser, and a spray mixed fluid consisting of a cleaning liquid and a gas is provided from the spray apparatus to the polishing surface to remove the polishing residue from the polishing surface. Done. This process is called "atomizing process".

As shown in FIG. 7, a draining mechanism 80 for draining the mixed fluid ejected from the spray apparatus 30 is provided in the spray apparatus 30 with respect to the direction in which the polishing table 22 rotates. It is located downstream of. A cover 82 covering the spraying device 30 and the draining mechanism 80 is disposed above the spraying apparatus 30 and the draining mechanism 80. The cover 82 is preferably made of a water repelling material such as fluorinated resin or the like. The cover 82 may be opened in the radial direction of the polishing table 22.

The draining mechanism 80 shown in FIG. 7 includes a contact member 84 for contacting the polishing pad 52 and a holder (not shown) for holding the contact member 84. The contact member 84 is preferably made of a material having a low coefficient of friction and a very high liquid sealing ability to further reduce wear. The draining mechanism 80 may comprise a pressure-adjusting press mechanism (not shown) for pressing the contact member 84 or the holder under controlled pressure, the contact member 84 being removed from the press mechanism. It may be brought into contact with the polishing pad 52 under pressure. The pressurization mechanism may be a cylinder mechanism or a ball screw mechanism for applying a fluid pressure such as pneumatic or hydraulic pressure.

According to the conventional CMP process, carrying out the atomization process, i.e. providing spraying fluid to the polishing surface during the polishing cycle, was not common, since the cleaning liquid supplied to the polishing surface changed the concentration of the polishing liquid. This is because the polishing ability of the polishing liquid is changed. According to this embodiment, since the draining mechanism 80 can immediately drain the cleaning liquid from the spray device 30 out of the polishing table 22, the polishing pad 52 can be kept clean at all times, thereby polishing It will stabilize the polishing characteristics of the device. Therefore, the polishing apparatus according to the present embodiment enables the spray apparatus 30 to carry out the spraying process (in-site spraying process) during the polishing cycle.

The dressing process (in-site dressing process) performed by the dresser 28 in the polishing cycle and the spraying process (in-site spraying process) performed by the sprayer 30 in the polishing cycle are polished in the polishing cycle. It may be combined with each other to condition the pads 52. As a result, the interval between polishing cycles can be reduced, thereby improving throughput of the polishing apparatus.

According to the example shown in FIG. 7, the contact member 84 extends in the radial direction of the polishing table 22. However, the contact member 84 may be inclined at a predetermined angle in the range of 0 ° to 90 ° from the radial direction of the polishing table 22.

The polishing unit 20 may be provided with a gas injection mechanism provided with a gas injection port to inject gas into the polishing pad 52 instead of or in addition to the contact member 84. 8 shows a perspective view of such a gas injection mechanism 86. As shown in FIG. 8, the gas injection mechanism 86 includes a plurality of gas injection holes 88 for injecting a gas such as dry air or dry nitrogen into the polishing pad 52, and injection amounts of gases and gas injection. And a control device (not shown) for controlling the pressure to be injected and the direction in which the gas is injected. The cleaning liquid from the spray device 30 is drained out of the polishing table 22 by the gas injected from the gas injection port 88. The gas injection port 88 is preferably in the shape of injecting the gas in a fan-like pattern, such as an air curtain. The gas injection port 88 may be in the form of a slit to control the direction in which the gas is injected.

The draining mechanism 80 in combination with the gas injection mechanism 86 can also immediately drain the cleaning liquid from the spraying device 30 out of the polishing table 22. Accordingly, the polishing pad 52 can be kept clean at all times, thereby making it possible to stabilize the polishing characteristics of the polishing apparatus.

Efforts have been made to create higher performance LSI circuits using finer interconnects to design faster operation, higher integration, and lower power consumption. In particular, technical development of finer interconnects has been carried out in accordance with expectations based on the International Technology Roadmap for Semiconductors (ITRS). The development of finer interconnects has been paralleled by converting interconnect materials to copper with lower resistivity and insulating materials to low-k materials with lower dielectric constants. It is expected that the requirements for the copper damascene planarization process (copper CMP process) will increase.

In order to achieve integration with low-k materials or porous low-k materials in the copper damascene planarization process, some countermeasures are made for materials that make finer interconnects and are broken during polishing due to the low mechanical strength of the materials. It is required to improve the planarization properties in an effort to take.

In order to satisfy the above requirements, it may be proposed to lower the pressure on the surface being treated, ie the polishing pressure. According to a conventional copper CMP process, after the copper complex is formed, the copper complex is mechanically removed, thereby gradually polishing the copper film. However, according to the polishing liquid used by the conventional CMP apparatus, the mechanical strength of the formed copper complex is very high, so that reducing the polishing pressure is likely to cause a decrease in the polishing rate.

In recent years, polishing liquids have been opened to form such low mechanical strength copper complexes in which the copper complex can be removed mechanically under low polishing pressure. Since the polishing liquid has a strong chemical reactivity, the amount and distribution of the polishing liquid supplied very much to the polished surface of the semiconductor wafer affect the polishing rate and the in-plane uniformity of the polishing rate.

According to the conventional CMP apparatus, as the polishing liquid is supplied from a fixed single polishing liquid supply port, the polishing liquid supplied therefrom to the polished surface of the semiconductor wafer is likely to have a localized distribution, so that in-plane uniformity of the polishing rate is achieved. It hurts the castle. This problem manifests itself in particular when the relative speed between the polishing surface and the semiconductor wafer is high. In addition, if the increase amount of the polishing liquid is wasted, the polishing cost increases. Accordingly, it is important that the polished surface of the semiconductor wafer can be supplied uniformly and efficiently to the polishing liquid.

According to the present embodiment, the polishing liquid supply port 57 (see Fig. 2) of the polishing liquid supply nozzle 26 is moved during the polishing process to uniformly and efficiently supply the polishing liquid to the polished surface of the semiconductor wafer. Done. Specifically, as shown in Fig. 1, the polishing liquid supply nozzle 26 of the present embodiment can be pivoted about the shaft 27, and is moved by a pivoting mechanism (moving mechanism) during the polishing process. It is pivoted about the shaft 27.

The polishing liquid is supplied from the polishing liquid supply nozzle 26 to the polishing pad 52. As the top ring 24 and the polishing table 22 move relative to each other, the polishing liquid supplied to the polishing pad 52 is supplied to the polished surface of the semiconductor wafer. When the polishing liquid supply nozzle 26 is pivoted about the shaft 27 and moves the polishing liquid supply port 57 (refer to FIG. 2) mounted at the front end during the polishing process, the polishing pad 52 The polishing liquid supplied to is properly distributed over the polishing pad 52 so that the top ring 24 and the polishing table 22 are uniformly supplied to the entire surface of the semiconductor wafer as the top ring 24 and the polishing table 22 move relative to each other. .

As described above, the polishing liquid supply nozzle 26 according to the present embodiment can uniformly distribute the polishing liquid supplied to the polished surface of the semiconductor wafer. As a result, the polishing rate is improved, and the in-plane uniformity of polishing is improved. As the polishing liquid is efficiently supplied, the amount of the polishing liquid used is reduced, and any wasteful consumption of the polishing liquid is reduced, thereby lowering the polishing cost.

In this embodiment, the polishing liquid supply nozzle 26 is pivoted along the arch path. However, the polishing liquid supply nozzle 26 may be moved according to other patterns. For example, the polishing liquid supply nozzle 26 may be moved in a linear, rotational, swinging or reciprocating manner. The polishing liquid supply nozzle 26 may be moved at a constant speed (eg 50 mm / s) or at a varying speed. The polishing liquid supply nozzle 26 may be combined with a liquid ratio control mechanism for changing the proportion of the polishing liquid supplied from the polishing liquid supply port 57 while the polishing liquid supply nozzle 26 is in motion. . The range scanned by the polishing liquid supply port 57 is preferably kept within the radius of the polishing table 22 and preferably covers the diameter of the semiconductor wafer being polished.

In the embodiment shown in FIG. 1, the polishing liquid supply nozzle 26 extends in the radial direction of the polishing table 22. However, as shown in FIG. 9, the polishing liquid supply nozzle 26 may be inclined at a predetermined angle in the range of 0 ° to 90 ° in the radial direction of the polishing table 22.

According to the CMP process, the semiconductor wafer is usually polished by the chemical mechanical action of the polishing liquid remaining on the polishing pad. To date, the polishing pad's ability to hold the polishing liquid is so low that most of the polishing liquid supplied to the polishing pad is not consumed and is discharged from the polishing pad. Since the polishing liquid is very expensive and has a great influence on the polishing cost, it is necessary to improve the working efficiency of the polishing liquid in order to reduce the polishing cost.

In a polishing process with a low polishing pressure (6.89 kPa (1 psi) or less) and a high relative speed between the semiconductor wafer and the polishing surface (2 m / s or more), when the thickness of the film of the polishing liquid supplied to the polishing surface is increased, Hydroplaning causes slippage between the semiconductor wafer and the polishing surface. This phenomenon per se, in particular when the polishing liquid is irregularly supplied to the polishing surface, for example, has a small concentric groove having a small cross section formed therein, or the polishing liquid is supplied to the polishing surface and from a single point of the polishing table. It is evident when fed to the center. When the hydroplaning phenomenon occurs, the polishing pressure does not act between the semiconductor wafer and the polishing surface, and the polishing rate is lowered. On the other hand, if the polishing liquid is positively discharged from the polishing surface, the amount of polishing liquid remaining on the polishing surface is reduced, resulting in a reduction in the working efficiency and polishing rate of the polishing liquid. Therefore, there has been a requirement for maintaining an appropriate amount of polishing liquid on the polishing surface in order to form a uniform film of polishing liquid on the polishing surface.

In order to satisfy this requirement, according to the present embodiment, the polishing pad 52 has grooves formed on its surface, each groove having a cross-sectional area of 0.38 cm ² or more. FIG. 10 shows a perspective view of the polishing pad 57 and FIG. 11 shows an enlarged vertical sectional view of the polishing pad 57. As shown in FIG. 10, the polishing pad 52 has a plurality of concentric grooves 90 formed on an upper surface thereof and spaced apart, for example, at a pitch P ₁ of 2 mm. According to the example shown in FIG. 11, each groove 90 has a width W ₁ of 0.5 mm, a depth D ₁ of 0.76 mm and a cross-sectional area of 0.38 mm ² . The depth of each groove 90 may be deeper than the depth of a conventional groove, for example 1 mm or more.

As shown in FIG. 12, the polishing pad 52 may further include a straight narrow slot 92 formed therein for interconnecting adjacent ones of the concentric grooves 90. The narrow slot 92 is effective in making the polishing liquid resist centrifugal force. The narrow slot 92 is preferably inclined at a predetermined angle α, for example 30 ° with respect to the circumferential direction of the polishing pad 52. Adjacent ones of the narrow slots 92 are preferably spaced apart from each other by a pitch P ₂ of 2 mm. Each narrow slot 92 is preferably about 30% of the width of the groove 90.

In the present embodiment, the polishing pad 52 has a concentric groove 90, but the polishing pad 52 may have a groove having a different shape. For example, the polishing pad 52 may have a spiral groove formed on an upper surface thereof, each of which has the same cross-sectional area as that of the concentric groove 90. If the spiral groove is inclined at a predetermined angle, for example, 45 ° with respect to the direction perpendicular to the circumferential direction of the polishing pad 52, the polishing liquid may be discharged from the polishing pad 52 under a predetermined centrifugal force.

The polishing pad 52 may have a plurality of holes formed in the surface thereof, each having an open area of 2.98 mm ² or more and a diameter of 1.95 mm or more instead of or in addition to the above-described groove 90. The holes having a large open area formed on the surface of the polishing pad 52 are effective in increasing the amount of polishing liquid accumulated by the polishing surface and increasing the working efficiency of the polishing liquid. The opening area of each of the holes is preferably 3.14 mm ² or more, more preferably 19.63 mm ² or more (diameter 5 mm or more). The holes may be circular or oval in shape, and may be arranged in a concentric pattern, a stagger pattern, or a grid pattern.

The CMP process mainly includes (1) a main polishing process for polishing the semiconductor wafer by pressing the semiconductor wafer to the polishing pad while supplying the slurry to the polishing pad, and (2) the semiconductor wafer after the semiconductor wafer is polished by the slurry. It comprises a water polishing process for polishing (washing) with water. In the main polishing step (1), excess film material on the surface of the semiconductor wafer is polished. In the water polishing process (2), the slurry deposits and debris produced in the main polishing process are washed on the surface of the semiconductor wafer.

As described above, as interconnects formed on semiconductor wafers become finer, an insulating film having a higher insulating capability is required. Porous low-k materials are known as materials for insulating films having higher insulating ability. However, porous low-k materials have very little mechanical strength. In this regard, the polishing pressure applied to the conventional CMP apparatus was in the range of 13.79 to 344.47 kPa (2 to 5 psi). Subsequently, the polishing pressure will require less than 13.79 kPa (2 psi) or less than 6.89 kPa (1 psi).

Semiconductor wafers with low-k materials must be polished, for example, under a low polishing pressure of 3.45 kPa (0.5 psi). Both the main polishing process and the water polishing process must be performed under low polishing pressure. However, if the water polishing process is performed under low polishing pressure, deposits such as slurries cannot be completely removed from the semiconductor wafer, and there is a possibility that they remain unremoved on the semiconductor wafer.

According to this embodiment, the water polishing process is performed as follows: after the main polishing process is performed on the semiconductor wafer under a low polishing pressure, the semiconductor wafer is subjected to the polishing under a pressure below the polishing pressure applied in the main polishing process. Pressed against pad 52, the polishing table 22 is rotated at a linear velocity of at least 1.5 m / s, preferably at least 2 m / s, more preferably at least 3 m / s. Pure water (DIW) is supplied to the polishing pad 52 at a flow rate of 1 l / min to polish the semiconductor wafer with water. In this way, the surface of the polished semiconductor wafer can be properly cleaned under low polishing pressure. Alternatively, the semiconductor wafer may be cleaned with a chemical solution, such as citric acid solution, which may accelerate removal of slurry deposits and debris from the semiconductor wafer, rather than pure water (DIW). As the chemical solution, other organic acids, organic alkalis or surfactants may be used. The time period of a typical cleaning process may be extended from 10 seconds to 20 seconds to remove slurry deposits and debris from the semiconductor wafer. However, since such an extended cleaning process lowers throughput, the above-described water polishing process or chemical solution cleaning process performed on the semiconductor wafer at high speed rotation is more preferable.

In the embodiment described above, the polishing liquid is supplied from the polishing liquid supply port 57 at the distal end of the polishing liquid supply nozzle 26. Differently designed polishing liquid supply nozzles may be used. For example, as shown in FIG. 13, the polishing liquid supply nozzle 26a includes a disk 100 having a polishing liquid supply port 57 and an arm 102 on which the disk 100 is mounted. It may be done. The arm 102 may not be pivoted, only the disk 100 may be rotated while supplying the polishing liquid from the polishing liquid supply port 57, or the arm 102 may be pivoted, or the polishing liquid The disk 100 may be rotated while supplying it from the polishing liquid supply port 57. Alternatively, the arm 102 may be moved linearly. The moving speed of the polishing liquid supply port 57, that is, the moving speed of the arm 102 and / or the rotating speed of the disk 100 may be changed while the polishing liquid supply nozzle 26a is operated. The polishing liquid supply nozzle 26a may be combined with a liquid ratio control mechanism for changing the proportion of the polishing liquid supplied from the polishing liquid supply port 57 while the polishing liquid supply nozzle 26a is in motion.

In Fig. 14, the polishing liquid supply nozzle 26b may be provided with a plurality of polishing liquid supply ports 57. The polishing liquid supply nozzle 26b may pivot, linearly move, rotate, swing or reciprocate. The moving speed of the polishing liquid supply nozzle 26b may be changed while the polishing liquid supply nozzle 26b is in operation. The polishing liquid supply nozzle 26b may be combined with a liquid ratio control mechanism for individually controlling the ratio of the polishing liquid supplied from each polishing liquid supply port 57 while the polishing liquid supply nozzle 26b is moved. have. The polishing liquid supply port 57 may have a different diameter. For example, the polishing liquid supply port 57 may have a diameter gradually decreasing in the radially inward direction of the polishing table 22. In FIG. 14, the polishing liquid supply nozzle 26b extends in the radial direction of the polishing table 22. However, as shown in FIG. 15, the polishing liquid supply nozzle 26b may be inclined at a predetermined angle in the range of 0 ° to 45 ° with respect to the radial direction of the polishing table 22.

Rather than moving the polishing liquid supply nozzle, the polishing liquid supply port may be moved in the polishing liquid supply nozzle. For example, as shown in FIG. 16, the polishing liquid supply nozzle 26c has a polishing liquid supply nozzle 57a which is linearly movable inside. Alternatively, the polishing liquid supply nozzle 57a may pivot, rotate, swing or reciprocate. The polishing liquid supply nozzle 26c may not be pivoted, or only the polishing liquid supply nozzle 57a may be moved while supplying the polishing liquid. Alternatively, the polishing liquid supply nozzle 26c may be pivoted, and the polishing liquid supply nozzle 57a may be moved while supplying the polishing liquid. The moving speed of the polishing liquid supply nozzle 57a may be changed while the polishing liquid supply nozzle 57a is moving. The polishing liquid supply nozzle 26c may be combined with a liquid ratio control mechanism for changing the proportion of the polishing liquid supplied from the polishing liquid supply port 57a while the polishing liquid supply nozzle 26c is in motion. As shown in Fig. 17, a plurality of polishing liquid supply nozzles 26c respectively shown in Fig. 16 may be combined with each other.

In Fig. 18, the polishing liquid supply nozzle 26d includes a disk 100 having a plurality of polishing liquid supply ports 57 and an arm 102 on which the disk 100 is mounted. The arm 102 may not be pivoted, only the disk 100 may be rotated while supplying the polishing liquid from the polishing liquid supply port 57, or the arm 102 may be pivoted, or the polishing liquid The disk 100 may be rotated while supplying it from the polishing liquid supply port 57. Alternatively, the arm 102 may be moved linearly. The moving speed of the polishing liquid supply port 57, that is, the moving speed of the arm 102 and / or the rotating speed of the disk 100 may be changed while the polishing liquid supply nozzle 26d is operated. The polishing liquid supply nozzle 26d may be combined with a liquid ratio control mechanism for individually controlling the ratio of the polishing liquid supplied from the polishing liquid supply port 57 while the polishing liquid supply nozzle 26d is in motion. have. The polishing liquid supply port 57 may have a different diameter. For example, the polishing liquid supply port 57 may have a diameter gradually decreasing in the radially inward direction of the polishing table 22. According to one example shown in Figure 18, the polishing liquid supply port 57 is located in a circle. However, the polishing liquid supply port 57 may be located on a plurality of concentric circles, or may be located on a single straight line or a plurality of straight lines.

In Fig. 19, the polishing liquid supply nozzle 26e comprises a hollow roll 104 having a plurality of polishing liquid supply ports 57 formed on the wall thereof. The roll 104 is rotatable about an axis parallel to the surface of the polishing table 22. The polishing liquid supply port 57 may be arranged in a linear pattern, a spiral pattern or a random pattern. The polishing liquid may be supplied from the polishing liquid supply port 57 as the roll 104 is rotated or the roll 104 is pivoted and rotated. The moving speed of the polishing liquid supply port 57, that is, the rotational speed of the roll 104 and / or the pivoting speed of the roll 104 may be changed while the polishing liquid supply nozzle 26e is in operation. The polishing liquid supply nozzle 26e may be combined with a liquid ratio control mechanism for individually controlling the ratio of the polishing liquid supplied from each of the polishing liquid supply ports 57 while the polishing liquid supply nozzle 26e is moved. The polishing liquid supply port 57 may have a different diameter. For example, the polishing liquid supply port 57 may have a diameter gradually decreasing in the radially inward direction of the polishing table 22. The roll 104 may be divided into a plurality of zones such that different polishing liquids are supplied along the longitudinal direction of the roll 104. According to the example shown in FIG. 19, the roll 104 of the polishing liquid supply nozzle 26b extends in the radial direction of the polishing table 22. However, the roll 104 may be inclined at a predetermined angle in the range of 0 ° to 45 ° with respect to the radial direction of the polishing table 22.

In Fig. 20, the polishing liquid supply nozzle 26f comprises a hollow roll 104 having a spiral slit 106 formed in the wall thereof. The polishing liquid may be supplied from the polishing liquid supply port 57 as the roll 104 is rotated or the roll 104 is pivoted and rotated. The rotational speed of the roll 104 and / or the pivoting speed of the roll 104 may be changed while the polishing liquid supply nozzle 26f is in operation. The polishing liquid supply nozzle 26f may be combined with a liquid speed control mechanism for controlling the speed of the polishing liquid supplied from the slit 106. The opening width of the slit 106 may be changed depending on the position. For example, the opening width of the slit 106 may gradually decrease in the radially inward direction of the polishing table 22. The roll 104 may be divided into a plurality of zones such that different polishing liquids are supplied along the longitudinal direction of the roll 104. According to the example shown in FIG. 20, the roll 104 of the polishing liquid supply nozzle 26f extends in the radial direction of the polishing table 22. However, the roll 104 may be inclined at a predetermined angle in the range of 0 ° to 45 ° with respect to the radial direction of the polishing table 22.

According to the example shown in FIG. 20, the roll 104 has a spiral slit 106. However, the roll 104 may have straight slits. FIG. 21 shows a perspective view of a polishing liquid supply nozzle 26g with a straight slit formed therein, and FIG. 22 shows a vertical sectional view of the polishing liquid supply nozzle 26g. As shown in FIG. 22, the polishing liquid supply nozzle 26g is mounted on the pressure holder 110 having the pressure chamber 208 formed therein, and the pressure holder 110, and the pressure holder 110. It includes a slit body 114 having a straight slit 112 formed therein extending downward from the (). The pressure holder 110 controls the pressure of the polishing liquid Q supplied to the pressure chamber 108 to adjust the flow rate of the polishing liquid Q discharged from the slit 112. Since the slit 112 is straight along the pressure holder 110, the polishing liquid Q is uniformly discharged along the slit 112. As shown in FIG. 23, the pressure chamber 108 may be divided into a plurality of compartments, and the polishing liquid Q having a different flow rate may be supplied to the compartment so that the polishing liquid Q is slit ( 112, along with the different flow rates. The polishing liquid supply nozzles 26g shown in FIGS. 21 and 22 may be arranged along the radial direction of the polishing table 22, or in the range of 0 ° to 45 ° with respect to the radial direction of the polishing table 22. FIG. It may be inclined at a predetermined angle.

The polishing liquid supply nozzle 26h shown in FIG. 24 may be used to dispense the polishing liquid supplied to the polishing pad 52. The polishing liquid supply nozzle 26h is provided with a fan-shaped distribution plate (distribution skirt) 116 for dispensing the polishing liquid Q injected from the polishing liquid supply port 57. According to this polishing liquid supply nozzle 26h, while the polishing liquid Q injected from the polishing liquid supply port 57 flows on the dispensing skirt 116, the polishing liquid Q is distributed in different directions so that the polishing pad is polished. Supplied to 52. The distribution skirt 116 may be provided with a groove or a resistance member for restricting the flow of the polishing liquid Q. The dispensing skirt 116 may have a rough surface to provide resistance to the flow of the polishing liquid Q flowing thereon. The distribution skirt 116 is preferably made of a chemical-resistant material such as fluorinated resin. As shown in FIG. 25, the polishing liquid supply nozzle 26g shown in FIG. 21 may be combined with the dispensing skirt 116.

The polishing liquid supply nozzle 26i shown in FIG. 26 may be used to dispense the polishing liquid supplied to the polishing pad 52. The polishing liquid supply nozzle 26i includes a disk-shaped nozzle body 118 and a distribution plate 120 mounted on the lower surface of the nozzle body 118. The polishing liquid is supplied to the polishing pad 52 through the center through holes (not shown) formed in the distribution plate 120 and the nozzle body 118. The distribution plate 120 has a bottom surface made of a resistive material. According to the polishing liquid supply nozzle 26i, the polishing liquid supplied from the polishing liquid supply port 57 is distributed in various directions by the lower surface of the distribution plate 120 to be provided to the polishing pad 52. The distribution plate 120 is preferably made of a chemical resistant material such as fluorinated resin.

FIG. 27 shows the polishing pad 52 for dispensing the polishing liquid Q supplied to the polishing pad 52 and disposed downstream of the polishing liquid supply nozzle 26 with respect to the direction in which the polishing table 22 rotates. The distribution plate (contact member) 122 is brought into contact with. The distribution plate 122 distributes the polishing liquid Q supplied from the polishing liquid supply nozzle 26 in the radial direction of the polishing table 22 to distribute the polishing liquid Q on the polishing pad 52. To equalize. The distribution plate 122 is preferably made of a wear-resistant elastic material such as fluorinated resin. The distribution plate 122 may extend in the radial direction of the polishing table 22 or may be inclined at a predetermined angle in the range of 0 ° to 45 ° with respect to the radial direction of the polishing table 22. have. The distribution plate 122 may be held stationary or may be pivoted, linear, rotated, swinged or reciprocated. The moving speed of the distribution plate 122 may change as it moves. As shown in FIG. 28, the distribution plate 122 may include a plurality of slits 124 for dispensing the polishing liquid Q supplied from the polishing liquid supply nozzle 26. The dimensions of the slit 124, such as width, height and pitch, are preferably adjustable by shutter or the like.

If the polishing liquid supplying means shown in Figs. 9 and 13 to 28 are used, the polishing pad 52 has a plurality of radially divided regions such as polishing pads having concentric circles, as shown in Fig. 10. It is preferable to have. The polishing pad 52 having the radially divided region is used to polish the semiconductor wafer while the polishing liquid is maintained in the radially divided region, rather than mixing the polishing liquid onto the polishing pad 52. To be efficiently supplied to the surface being

As shown in FIG. 29, the conventional CMP apparatus 500 having a plurality of polishing liquid supply ports has a high speed polishing liquid circulation system 502 disposed outside the CMP apparatus 500 for circulating the polishing liquid at high speed. ). A single polishing liquid supply line 504 is connected to the polishing liquid circulation system 502 from the CMP apparatus 500. In the CMP apparatus 500, the polishing liquid supply line 504 is branched into a plurality of lines 506 connected to respective polishing liquid supply ports. Depending on the shape of the polishing liquid supply nozzle, the polishing liquid is easy to be supplied at a different ratio from the polishing liquid supply port, and the polishing liquid supply nozzle must be adjusted or combined by a valve for uniformly supplying the polishing liquid to the polishing pad. do.

According to the present embodiment, as illustrated in FIG. 30, a high-speed polishing liquid including a polishing liquid tank 202, a pressure pump 204, a back-pressure valve 206, and a pipe 208. The circulation system 210 and the polishing apparatus 200 are combined. The plurality of polishing liquid supply lines 212 extend from each polishing liquid supply port 57 and are directly connected to the pipe 208 of the high speed polishing liquid circulation system 210. The form shown in FIG. 30 makes it possible to uniformly supply the polishing liquid to the semiconductor wafer to be polished, thereby improving the polishing rate and greatly improving the in-plane uniformity of the polishing rate.

As shown in FIG. 30, the polishing liquid supply line 212 includes respective fluid pressure valves 214 as flow control valves for adjusting the flow rate of the polishing liquid supplied from the polishing liquid supply port 57. As shown in FIG. As shown in FIGS. 31A and 31B, each fluid pressure valve 214 has a pipe compression section for reducing the diameter of one of the flexible pipes 212a of the polishing liquid supply line 212 under fluid pressure. 216; The pipe compression portion 216 is disposed around the pipe 212a. As shown in FIG. 31B, when the pipe 212a is compressed by the pipe compression unit 216 under fluid pressure, the flow rate of the polishing liquid Q passing through the pipe 212a is reduced. The pipe 212a is compressed by the pipe compression unit 216 under fluid pressure, thereby preventing the pipe 212a from being excessively worn.

The retaining ring of the top ring controls the polishing profile of the workpiece (semiconductor wafer) to be polished by (1) holding the outer edge of the workpiece and (2) pressing itself against the polishing surface (polishing pad). As described above, if a polishing liquid for forming a copper complex having a low mechanical strength is used under a low polishing surface pressure, excessively pressing the retaining ring against the polishing surface may not be sufficient to supply the polishing liquid to the surface of the workpiece to be polished. Easy to restrict Therefore, the load applied to press the retaining ring against the polishing surface should be as small as possible. However, if the load applied to press the retaining ring against the polishing surface is too small, the workpiece held by the retaining ring is likely to be displaced from the retaining ring. Therefore, even if the load applied to press the retaining ring against the polishing surface is small, measures to prevent the workpiece from being displaced from the retaining ring are required.

To satisfy this requirement, as shown in FIG. 32, the presser 300 and the semiconductor for pressing the polishing pad 52 to adjust the contact state between the semiconductor wafer W and the polishing pad 52. A retainer ring 356 may be used that includes a ring-shaped guide 302 to prevent the wafer W from being displaced from the top ring 24. The guide 302 is located radially inward of the presser 300 in proximity to the semiconductor wafer W. According to the retainer ring 356, even if the polishing pressure is low, the retainer ring 356 controls the polishing profile of the semiconductor wafer W while preventing the semiconductor wafer W from displacing from the top ring 24. can do.

The guide 302 is adjustable at an appropriate position in the vertical direction with a screw or air cylinder to adjust the height between the surface of the polishing pad 52 and the guide 302. The guide 302 preferably has a radius of 6 mm or less, and is preferably made of a material having a low level of rigidity.

In the CMP process for planarizing the copper damascene interconnect for semiconductor device manufacturing, the copper film is completely removed to the barrier metal while leaving the copper interconnect. As shown in FIGS. 33A-33C, the process of removing the copper film to the barrier metal is a first step in which most of the initial copper film 400 is quickly removed and the initial steps are shortened to leave some copper film 400a. (Bulk copper polishing process, see FIGS. 33A and 33B), and the second step of completely removing the remaining copper film 400a to the barrier metal 402, leaving the interconnect 400b (copper clearing process, FIG. 33B). And FIG. 33C).

In the bulk copper polishing process, the initial step is reduced (flattened) as much as possible, and the copper film 400a remains uniformly as thin as possible, thereby reducing the burden in the copper clearing process. For example, the thickness of the copper film 400a remaining after the bulk copper polishing process should be in the range of 100 to 150 nm, preferably 100 nm or less, or more preferably 50 nm or less. In general, as shown in FIG. 34A, the copper clearing process is performed under reduced polishing pressure to reduce dishing 410 and corrosion 412 after removal of the copper film.

The conventional CMP apparatus has determined the timing for the process switching based on the information about the film thickness at a predetermined position in the wafer plane. According to this method, since the timing for the process switching is determined irrespective of the distribution of the film thickness during the polishing process, even when the polishing profile is changed, when the film thickness at the position being measured on the wafer reaches a predetermined value. Process conversion will be carried out.

If a much thicker copper film is present at another location on the wafer than at the location where the thickness of the remaining copper film is being measured, as shown in FIG. 34B, the remaining conductive film 414 ends the next copper clearing process. It can happen afterwards. On the contrary, if there is a copper film at another location on the wafer that is much less thick than at the location where the thickness of the remaining copper film is being measured, as shown in FIG. 34A, dishing 410 and Corrosion 412 may also occur.

This problem can be avoided by the following process: Upon transition from the bulk copper polishing process to the copper clearing process, the film thickness distribution of the copper film is preset and stored in the memory. In the bulk copper polishing process performed on the semiconductor wafer, the film thickness distribution of the copper film on the semiconductor wafer is obtained from the eddy current sensor 58 (see Fig. 2). According to the simulation software program, the preset film thickness distribution and the obtained film thickness distribution are instantaneously compared with each other, and the polishing conditions necessary for obtaining the preset film thickness distribution are simulated. Based on the simulated polishing conditions, the top ring 24 controls the polishing profile to obtain a preset film thickness distribution. For example, the top ring 24 increases the polishing rate for areas where the degree of polishing is insufficient in the current film thickness distribution. The polishing profile control performed in this way allows the remaining copper film to have a uniform thickness or to have a predetermined film thickness distribution immediately before the copper clearing process. If the actual film thickness distribution matches the preset film thickness distribution, the bulk copper polishing process is converted to the copper clearing process.

The process makes it possible to reliably obtain the final desired film thickness distribution while monitoring the actual polishing configuration (film thickness distribution). Since the bulk copper polishing process can always be converted to the copper clearing process at the desired film thickness distribution, the copper clearing process is always unaffected by handling variations in the bulk copper polishing process, i.e. variations in polishing rate and polishing profile. May be initiated under certain conditions. Accordingly, any excessive burden on the next copper clearing process can be minimized. This process not only reduces the dishing 410 and corrosion 412 after the copper clearing process, but also contributes to the reduction of time spent by the copper clearing process, namely excessive polishing time, increased productivity, and reduced polishing costs. Done.

After the conductive film on the semiconductor wafer is polished in the process of forming the interconnect, any defects present, such as residues, scratches and pits 416 of the conductive film 414 (FIGS. 34A and 34B) As well as the subsequent process of forming the interconnect, as well as the electrical properties of the electrical circuit finally formed on the semiconductor wafer. As a result, it is desirable to eliminate these defects at the end of the polishing process.

According to the CMP process, the residue of the conductive film 414 may be erased by overpolishing the semiconductor wafer to a thickness thicker than the thickness of the initial film. In general, overpolishing a semiconductor wafer for an extended period of time is likely to cause dishing 410 and corrosion 412 in the interconnect area of the semiconductor wafer, as shown in FIG. 34A. In addition, scratches and pits 416 are unavoidable because of the mechanical polishing action on the semiconductor wafer.

In general, the remaining conductive film 414 cannot be removed by ordinary polishing, so it must be removed by overpolishing. However, overpolishing is likely to cause dishing 410, corrosion, scratches and pits 416 on the semiconductor wafer as described above. In order to eliminate these defects, the bulk copper polishing process is performed by CMP, and the subsequent copper clearing process by CMP is stopped when the remaining copper film reaches a thickness of 50 nm or less. Then, a copper clearing process is performed by a chemical etching process to remove the copper film. The copper clearing process performed by the chemical etching process without the mechanical polishing action can polish the copper film without causing a defect.

The etchant used in the chemical etching process may be an acid such as sulfuric acid, nitric acid, halogen acid (especially hydrofluoric acid or hydrochloric acid), an alkali such as aqueous ammonia, or a mixture of an oxidant such as hydrogen peroxide and an acid such as hydrogen fluoride or sulfuric acid. . In the bulk copper polishing process, the thickness of the conductive thin film is measured, and when the measured thickness reaches a predetermined thickness such as 100 nm or less, the bulk copper polishing process is preferably converted to the copper clearing process. The thickness of the conductive thin film may include an optical sensor for applying light to the conductive thin film to measure the film thickness, a vortex sensor for detecting vortices generated in the conductive thin film to measure the film thickness, and a film thickness. It may be measured by at least one of a torque sensor for detecting the running torque of the polishing table 22, and an ultrasonic sensor for applying ultrasonic energy to the conductive thin film to measure the film thickness.

The chemical etching process is not limited to a bulk copper polishing process for forming a copper thin film into a CMP apparatus, and may be combined with other processes. Specifically, after various processes for forming a flat conductive thin film on the substrate, the conductive thin film may be removed by a chemical etching process.

For example, after the thin film is formed by an electrolytic polishing process, the formed thin film may be removed by a chemical etching process. The electrolytic polishing process is effective in reducing scratches and pits 416 because it does not involve mechanical action. However, if a conductive film that cannot make an electrical connection such as a conductive film that remains slightly on the insulating material occurs, the electrolytic polishing process cannot remove this remaining conductive film. However, the flat conductive thin film formed by the electrolytic polishing process can be removed by a chemical etching process that requires no electrical connection at all, without generating a defect. The electrolytic polishing process is not limited to any particular type. For example, an electrolytic polishing process using an ion exchange device or an electrolytic polishing process without using an ion exchange device may be adopted. The electrolytic polishing process is preferably carried out using ultrapure water, pure water or a liquid or electrolyte having a conductivity of 500 μS / cm or less. For example, the electrolytic polishing process may be performed by an electrolytic treatment apparatus disclosed in Japanese Patent Laid-Open No. 2003-145354.

After the thin film is formed by the flat plating process, the formed thin film may be removed by a chemical etching process. Formation and removal of the copper film Cu have been described above. However, the present invention also applies to the formation and removal of other films. For example, after the conductive thin film containing at least one of Ta, TaN, WN, TiN and Ru is formed, the formed thin film may be removed by a chemical etching process.

<Example 1>

The polishing apparatus shown in Fig. 35 was used to polish the semiconductor wafer while the polishing liquid supply nozzle 26 was actually swinged in the polishing process. FIG. 36A is a graph showing the polishing rate of the semiconductor wafer polished by the polishing apparatus shown in FIG. FIG. 36B is a graph showing the polishing rate of the semiconductor wafer polished by the polishing apparatus shown in FIG. 35 without the polishing liquid supply nozzle 26 swinging in the polishing process. Comparison between these graphs shows that the in-plane uniformity of the polishing ratio of the semiconductor wafer is higher when the polishing liquid supply nozzle 26 is swinging in the polishing process.

<Example 2>

The polishing apparatus 200 shown in FIG. 30 was used to polish the semiconductor wafer while the polishing liquid was supplied from the plurality of polishing liquid supply ports 57 in the polishing process. The polishing pressure is 3.45 kPa (0.5 psi). FIG. 37 is polished by the polishing apparatus (multi) shown in FIG. 30 in comparison with the removal rate of the semiconductor wafer polished by the polishing apparatus while supplying the polishing liquid from one polishing liquid supply port (single). It is a graph showing the removal rate of the semiconductor wafer. It can be seen from FIG. 37 that the in-plane uniformity of the removal rate of the semiconductor wafer was higher when polishing was performed while feeding the polishing liquid from the plurality of polishing liquid supply ports.

While certain preferred embodiments of the present invention have been shown and described in detail, it is evident that various modifications and changes can be made without departing from the scope of the appended claims.

The polishing apparatus of the present invention can be used to polish the surface of a workpiece such as a semiconductor wafer to a planar finish.

Claims (70)

In the polishing apparatus, A polishing table having a polishing surface; A top ring for holding the workpiece to be polished to press the workpiece against the polishing surface; A polishing liquid supply nozzle having a polishing liquid supply port for supplying a polishing liquid to the polishing surface; And The polishing liquid supply port is moved to move the polishing liquid supply nozzle during polishing so as to uniformly distribute the polishing liquid supplied from the polishing liquid supply port over the entire surface of the workpiece by the relative movement of the workpiece and the polishing surface. Polishing apparatus comprising a moving mechanism for moving the. The method of claim 1, And the moving mechanism moves the polishing liquid supply nozzle in one or more of pivoting, reciprocating, rotating and linear motions. The method of claim 1, And the moving mechanism changes the moving speed of the polishing liquid supply nozzle while the polishing liquid supply nozzle is in motion. The method of claim 1, And a liquid ratio control mechanism for controlling the ratio of the polishing liquid supplied from the polishing liquid supply port while the polishing liquid supply nozzle is in motion. delete The method of claim 1, And the polishing liquid supply nozzle comprises a plurality of polishing liquid supply ports. The method of claim 6, And the polishing liquid supply holes are different in diameter. The method of claim 6, And a liquid ratio control mechanism for individually controlling the ratio of the polishing liquid supplied from the polishing liquid supply ports. The method of claim 1, And the polishing liquid supply nozzle extends in a radial direction of the polishing table. The method of claim 1, And the polishing liquid supply nozzle is inclined at a predetermined angle with respect to the radial direction of the polishing table. In the polishing apparatus, A polishing table having a polishing surface; A top ring for holding the workpiece to be polished to press the workpiece against the polishing surface; A plurality of polishing liquid supply ports for supplying a polishing liquid to the polishing surface; And A liquid ratio control mechanism for controlling the ratio of the polishing liquid supplied from the polishing liquid supply ports to distribute the polishing liquid evenly over the entire surface of the workpiece by the relative motion of the workpiece and the polishing surface. Polishing apparatus comprising a. The method of claim 11, And the liquid ratio control mechanism individually controls the ratio of the polishing liquid supplied from the polishing liquid supply ports. The method of claim 11, And the polishing liquid supply holes are different in diameter. The method of claim 11, And a polishing liquid supply nozzle having the polishing liquid supply holes. The method of claim 14, And the polishing liquid supply nozzle extends in a radial direction of the polishing table. The method of claim 14, And the polishing liquid supply nozzle is inclined at a predetermined angle with respect to the radial direction of the polishing table. delete delete delete delete delete delete delete In the polishing apparatus, A polishing table having a polishing surface; A top ring for holding the workpiece to be polished to press the workpiece against the polishing surface, the top ring having a retainer ring for holding an outer edge of the workpiece; The retainer ring has a groove formed in a surface in contact with the polishing surface, the groove extending between an outer circumferential surface and an inner circumferential surface of the retainer ring; And the groove has an opening ratio in the range of 10% to 50% at the outer circumferential surface of the retaining ring. The method of claim 24, And the top ring rotates at a rotational speed in a range of 1/3 to 1 / 1.5 of the rotational speed of the polishing table. The method of claim 25, And the top table and the top ring rotate in one direction. The method of claim 25, And the top table and the top ring rotate in opposite directions, respectively. The method of claim 24, The retaining ring is, A presser for pressing the polishing surface to adjust a contact state between the workpiece and the polishing surface; And And a guide for preventing the workpiece from being displaced from the top ring. The method of claim 28, And the guide is located closer to the workpiece than the presser. The method of claim 28, And the guide is adapted to adjust the height from the polishing surface. The method of claim 28, And the guide has a ring shape. The method of claim 28, And the guide has a radial width of up to 6 mm. The method of claim 28, And the guide is made of a less rigid material than the object to be polished. In the polishing apparatus, A polishing table having a polishing surface; A top ring for holding the workpiece to be polished to press the workpiece against the polishing surface; A polishing liquid supply port for supplying a polishing liquid to the polishing surface; And A relative movement mechanism for moving the polishing surface and the workpiece at a relative speed of at least 2 m / s from each other, And the polishing surface has a groove having a cross-sectional area of at least 0.38 mm ² . The method of claim 34, wherein And the groove comprises a plurality of concentric grooves. 36. The method of claim 35 wherein And the polishing surface comprises narrow slots interconnecting the grooves. The method of claim 36, And the narrow slots comprise straight grooves inclined in the circumferential direction of the polishing table. The method of claim 34, wherein And the polishing surface has a plurality of holes formed therein having an open area of at least 2.98 mm ² . The method of claim 34, wherein And the polishing liquid supply port comprises a plurality of polishing liquid supply ports. In the polishing apparatus, A polishing table having a polishing surface; A saw for holding the workpiece to be polished to press the workpiece against the polishing surface; And It comprises a polishing liquid supply port for supplying a polishing liquid to the polishing surface, And the polishing surface has a plurality of holes formed therein having an open area of at least 2.98 mm ² . The method of claim 40, And each of the holes has an open area of at least 19.63 mm ² . delete In the polishing apparatus, A polishing table having a polishing surface; A top ring for holding the workpiece to be polished to press the workpiece against the polishing surface; A fluid injection mechanism for injecting a mixed fluid of a cleaning liquid and a gas into the polishing surface; And And a discharge mechanism for discharging said mixed fluid from said polishing surface, said discharge mechanism being disposed downstream of said fluid injection mechanism with respect to the direction in which said polishing surface moves. The method of claim 43, And the discharge mechanism includes a contact member for contacting the polishing surface. delete delete The method of claim 44, And the contact member extends in the radial direction of the polishing table. The method of claim 44, And the contact member is inclined at a predetermined angle with respect to the radial direction of the polishing table. The method of claim 43, The discharge mechanism, A gas injection port for injecting gas into the polishing surface; And And a control device for controlling at least one of a gas amount injected from the gas injection port, a gas pressure injected from the gas injection port, and a gas direction injected from the gas injection port. The method of claim 49, And the gas injection port extends in a radial direction of the polishing table. The method of claim 49, And the gas injection port is inclined at a predetermined angle with respect to the radial direction of the polishing table. The method of claim 43, And a cover disposed in a covering relationship to the fluid injection mechanism and the discharge mechanism. The method of claim 43, And the fluid injection mechanism and the discharge mechanism are disposed upstream of the top ring with respect to the direction in which the polishing surface moves. The method of claim 43, And a dresser for dressing the polishing surface. A method of polishing a workpiece by pressing the workpiece against the polishing surface of the polishing table and moving the polishing surface and the workpiece relative to each other, While the workpiece is polished, injecting a mixed fluid of a cleaning liquid and a gas from a fluid spray mechanism to the polishing surface; And And discharging said mixed fluid from said polishing surface by a discharge mechanism disposed downstream of said fluid ejection mechanism with respect to the direction in which said polishing surface moves. The method of claim 55, While the workpiece is polished, dressing the polishing surface further. In the method of polishing the workpiece, Polishing the workpiece under low pressure of up to 13.79 kPa; And Then polishing the workpiece under low pressure of up to 13.79 kPa at a relative speed of at least 2 m / s between the workpiece and the polishing surface while supplying water to the workpiece. In the method of polishing the workpiece, Polishing the workpiece under low pressure of up to 13.79 kPa; And Then polishing the workpiece under low pressure of up to 13.79 kPa at a relative speed of at least 2 m / s between the workpiece and the polishing surface while supplying a chemical solution to the workpiece. 59. The method of claim 58, The chemical solution is a polishing method, characterized in that comprises a chemical solution for promoting the separation of the polishing solution adhered to the surface of the workpiece. 59. The method of claim 58, The chemical solution is a polishing method, characterized in that comprises a chemical solution containing at least one of an organic acid, an organic alkali and a surfactant. In the method of polishing the workpiece, Polishing the workpiece to remove from the first stage a substantial portion of the first film formed on the workpiece; Polishing the workpiece to remove the remaining portion of the first film until the second film on the workpiece is exposed at the second stage while leaving interconnect areas; Presetting a film thickness distribution for the first film upon transition from the first stage polishing to the second stage polishing; Measuring a thickness of the first film by using a vortex sensor in the first stage polishing to obtain a film thickness distribution of the first film; And And adjusting the polishing conditions in the second stage polishing so that the obtained film thickness distribution of the first film is equal to the film thickness distribution preset for the first film. 62. The method of claim 61, And the first stage polishing is switched to the second stage polishing when the obtained film thickness distribution of the first film is equal to the film thickness distribution preset for the first film. In a method of forming an interconnect on a substrate, Forming a flat conductive thin film on the substrate; And Thereafter, removing the planar conductive thin film from the substrate by a chemical etching process. The method of claim 63, wherein And forming a flat conductive thin film is performed by a chemical mechanical polishing process. The method of claim 63, wherein Forming a flat conductive thin film is performed by an electrolytic polishing process. The method of claim 65, And the electrolyte polishing process comprises an electrolyte polishing process using an ion exchanger. The method of claim 63, wherein And wherein said chemical etching process is performed using an etchant comprising at least one of sulfuric acid, nitric acid, halogen acid, hydrogen peroxide, aqueous ammonia and mixtures thereof. The method of claim 63, wherein Wherein the thickness of the conductive thin film is measured in the step of forming the flat conductive thin film, and the forming of the flat conductive thin film is terminated when the measured thickness reaches a predetermined thickness. The method of claim 68, wherein And the predetermined thickness is at most 100 nm. The method of claim 63, wherein And the conductive thin film contains at least one of Cu, Ta, TaN, WN, TiN, and Ru.

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