JP2009253031A - Chemical mechanical polishing apparatus and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a chemical mechanical polishing efficiency by polishing a polishing target, dressing a polishing pad, and forming a film of a hydrophilic material to the polishing pad at the same time. <P>SOLUTION: The chemical mechanical polishing (CMP) apparatus includes: a polishing table 12; a head 11; a slurry supply 16; a mechanical conditioner 14; and a chemical conditioner 15. A polishing pad 13 is held on the polishing table 12. A holder mechanism for holding the polishing target 17 is formed on the lower surface of the head 11. The slurry supply 16 drops a slurry 18 on the surface of the polishing pad 13. The mechanical conditioner 14 is provided to dress the polishing pad. The chemical conditioner 15 has an arm 31, a reservoir 33 for storing a hydrophilic material, and a nozzle 32 for supplying the hydrophilic material to the polishing pad. The chemical conditioner 15 is provided to coat the polishing pad 13 with the hydrophilic material and to form a film of the hydrophilic material on the polishing pad 13, thus enhancing a wetting property of the polishing pad 13 to the slurry 18. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a chemical mechanical polishing apparatus that chemically and mechanically polishes the surface of a wafer, and a chemical mechanical polishing method.

  A chemical mechanical polishing (CMP) apparatus is an apparatus for polishing and planarizing a surface of an object to be polished such as a semiconductor wafer.

  FIG. 5A is a schematic top view of a conventional general CMP apparatus, and FIG. 5B is a schematic side view of a general CMP apparatus. A conventional general CMP apparatus includes a polishing table 52, a head 51, a slurry supply unit 56, and a mechanical conditioner 54.

  The polishing table 52 has a disk shape, and a polishing pad 53 is held on the polishing table 52. The polishing table 52 rotates around an axis perpendicular to the surface of the polishing table 52.

  The head 51 is installed to face the polishing pad 53, and a polishing object 57 such as a wafer is held on the facing surface of the head 51 and the polishing pad 53. As the head 51 rotates and swings, the polishing object 57 is polished by pressing the polishing object 57 against the polishing pad 53.

  The slurry supply unit 56 drops the slurry 58, which is an abrasive, on the polishing pad 53. The polishing pad 53 is polished by the slurry particles 61 in the slurry 58.

  The mechanical conditioner 54 sharpens the polishing pad 53 and improves the wettability of the polishing pad 53 with the slurry 58. The slurry particles 61 are held in a recess formed on the surface of the polishing pad 53 by sharpening.

  FIG. 6A is a cross-sectional view of the polishing pad 53 that has been sufficiently sharpened, in a plane perpendicular to the surface of the polishing pad 53. A number of recesses 62 are formed on the surface 64 of the polishing pad that has been sufficiently sharpened. The slurry particles 61 are held in these recesses 62. Thereby, the polishing object 57 is stably polished.

  Thus, the conventional general chemical mechanical polishing apparatus sharpens the polishing pad 53 in order to hold the slurry particles 61 substantially uniformly on the surface 64 of the polishing pad.

  However, if the sharpening is insufficient for some reason, as shown in FIG. 6B, the number of recesses 62 formed on the surface 64 of the polishing pad decreases. When the sharpening is insufficient, the slurry particles 61 held on the surface 64 of the polishing pad are reduced, and there is a problem that the polishing becomes unstable.

  In order to solve the above problems, Patent Document 1 describes that the surface of a polishing pad is hydrophilized using a chemical solution or a surfactant having an oxidizing action. Specifically, the polishing pad is hydrophilized using a chemical solution or a surfactant having an oxidizing action as a CMP start-up process before polishing the object to be polished. Next, after rinsing to remove the chemical solution and the surfactant, the polishing pad is attached to the CMP apparatus. Thereafter, dressing of the polishing pad is performed, and after CMP of the dummy wafer, dressing of the polishing pad is performed again.

As described above, the chemical mechanical polishing (CMP) method described in Patent Document 1 improves the wettability with the slurry by hydrophilizing the surface of the polishing pad with an oxidizing chemical solution or a surfactant. ing.
JP 2000-173958 A

  In the CMP method described in Patent Document 1, it is necessary to perform rinsing in order to remove a chemical solution and a surfactant having an oxidizing action from the surface of the polishing pad. Therefore, the chemical mechanical polishing process is increased and the polishing efficiency is reduced.

  Further, the CMP method described in Patent Document 1 has a problem that the polishing efficiency is lowered because the dummy wafer is polished after the polishing pad is hydrophilized.

  An object of the present invention is to provide a chemical mechanical polishing apparatus and a chemical mechanical polishing method capable of improving polishing efficiency in view of the problems of the background art.

  The chemical mechanical polishing apparatus of the present invention includes a polishing pad for polishing an object to be polished and a mechanical conditioner for sharpening the surface of the polishing pad. The chemical mechanical polishing apparatus further includes a chemical conditioner for applying a hydrophilic material to the surface of the polishing pad.

  The chemical mechanical polishing method of the present invention comprises a holding step for holding a polishing object on a polishing pad, a polishing step for polishing the polishing object with a polishing pad, and a surface of the polishing pad being sharpened, and A mechanical conditioning step of dripping the slurry, and a chemical conditioning step of applying a hydrophilic material to the surface of the polishing pad.

  According to the present invention, the polishing efficiency can be improved.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A is a schematic top view of a chemical mechanical polishing (CMP) apparatus according to an embodiment of the present invention. FIG. 1B is a schematic side view of the CMP apparatus.

  The CMP apparatus of this embodiment includes a polishing table 12, a head 11, a slurry supply unit 16, a mechanical conditioner 14, and a chemical conditioner 15.

  The polishing table 12 is disk-shaped and has a structure that can rotate around an axis perpendicular to the disk surface. For example, the polishing table 12 rotates during polishing of a polishing object 17 such as a wafer. A polishing pad 13 is held on the polishing table 12. The polishing pad 13 is used for polishing the polishing object 17.

  The head 11 has a disk shape and is installed with the lower surface of the head 11 facing the polishing pad 13. A holding mechanism (not shown) for holding the polishing object 17 is formed on the lower surface of the head 11. As an example of a method for holding the polishing object 17, there is a method in which the space between the polishing object 17 and the head 11 is reduced and adsorbed.

  The head 11 has a mechanism that can rotate around an axis perpendicular to the surface of the head 11. When polishing the polishing object 17, the head 11 rotates and the polishing object 17 held on the lower surface of the head 11 is pressed against the polishing pad 13.

  The slurry supply unit 16 is provided above the polishing pad 13, and drops slurry 18, which is an abrasive, on the surface of the polishing pad 13. Any known material can be used for the slurry.

  The slurry 18 is preferably dropped near the center of the polishing pad 13. This is because the slurry 18 reaches the periphery of the polishing pad 13 due to the centrifugal force generated by the rotation of the polishing table 12.

  2A is a schematic side view of the mechanical conditioner 14, and FIG. 2B is a schematic bottom view of the mechanical conditioner 14. The mechanical conditioner 14 has an arm portion 21 and a pedestal portion 22 and is provided for sharpening the polishing pad. The arm portion 21 supports the pedestal portion 22 on one end side thereof, and can swing around the other end side.

  The pedestal portion 22 has a disk shape, and the surface of the pedestal portion 22 is disposed to face the polishing pad 13. Abrasive grains are electrodeposited on the surface of the board facing the polishing pad 13 as the abrasive grain electrodeposition portion 23 (see FIG. 2B). As the abrasive grains, diamond having a uniform crystal shape can be used. The pedestal 22 has a structure that can rotate around an axis perpendicular to the board surface.

  When the polishing pad 13 is sharpened, the pedestal 22 rotates as it is pressed against the polishing pad 13. Along with this, the arm portion 21 swings to sharpen the polishing pad 13.

  FIG. 3A is a schematic side view of the chemical conditioner 15, and FIG. 3B is a schematic bottom view of the chemical conditioner 15. The chemical conditioner 15 includes an arm portion 31, a storage portion 33 that stores a hydrophilic material, and a nozzle 32 that supplies the hydrophilic material to the polishing pad. The chemical conditioner 15 is provided for applying a hydrophilic material to the polishing pad 13.

  One end of the arm part 31 supports the nozzle 32, and the other end of the arm part 31 is connected to the storage part 33. A channel 34 is formed inside the arm portion 31, and the hydrophilic material in the storage portion 33 can flow to the nozzle 32. The arm portion 31 can swing around an end portion connected to the storage portion 33, and the nozzle 32 supported at one end of the arm portion 31 can swing.

  The nozzle 32 is an outflow surface from which the hydrophilic material flows out, and the outflow surface is disposed to face the polishing pad. A plurality of outflow ports 35 through which the hydrophilic material flows out are formed on the outflow surface of the nozzle 32. The outflow port 35 is connected to the flow path 34 formed in the arm portion 31 and flows out the hydrophilic material. As long as a hydrophilic material can be applied to the polishing pad 13, the number of the outlets 35 may be any number.

  The hydrophilic material stored in the storage portion 33 flows out from the outlet 35 of the nozzle 32 through the flow path 34 formed in the arm portion 31. In this way, a hydrophilic material can be applied to the polishing pad 13 and a film of the hydrophilic material can be formed on the surface of the polishing pad 13.

  The nozzle 32 is rotatably supported at the connecting portion with the arm portion 31. When applying the hydrophilic material, the nozzle 32 rotates as the arm portion 31 swings. As a result, a uniform hydrophilic material film can be formed on the surface of the polishing pad 13.

  For example, titanium oxide can be used as the hydrophilic material. Since the hydrophilicity of titanium oxide is extremely high, the wettability with the slurry 18 can be greatly improved by applying titanium oxide to the surface of the polishing pad 13.

  Thus, the chemical conditioner 15 forms a hydrophilic material film on the polishing pad 13 and improves the wettability of the polishing pad 13 to the slurry 18. As a result, stable chemical mechanical polishing is possible, and polishing efficiency is improved.

  Further, since no acidic chemical solution or surfactant is used to make the polishing pad 13 hydrophilic, it is not necessary to perform rinsing after making the polishing pad 13 hydrophilic. Therefore, the chemical mechanical polishing process is simplified.

  Further, since it is not necessary to rinse the rinse wafer or the dummy wafer, it is possible to apply a hydrophilic material to the polishing pad while the polishing object 17 is being polished and the polishing pad 13 is being sharpened. That is, the polishing of the polishing object 17, the sharpening of the polishing pad 13, and the formation of the hydrophilic material film on the polishing pad 13 can be performed at the same time, and the polishing efficiency can be improved.

  In the CMP apparatus of the present embodiment, the head 11, the mechanical conditioner 14, and the chemical conditioner 15 are installed above the polishing pad 13 so as not to interfere with each other's processing.

  Next, a chemical mechanical polishing (CMP) method according to an embodiment of the present invention will be described. The CMP method includes a holding process, a polishing process, a mechanical conditioning process, and a chemical conditioning process.

  In the holding step, the polishing object 17 is held facing the polishing pad 13 on the head 11 of the chemical mechanical polishing apparatus. Then, the polishing table 12 is rotated.

  In the polishing step, the polishing target 17 held by the head 11 is pressed against the polishing pad 13 and the head 11 is swung and rotated.

  In the mechanical conditioning step, the polishing pad 13 is sharpened and the slurry is dropped onto the polishing pad 13. Specifically, the mechanical conditioner 14 is pressed against the polishing pad 13 to swing the arm portion 21, and the pedestal portion 22 is rotated. As a result, the abrasive grains electrodeposited on the pedestal portion 22 scrape the surface of the polishing pad 13 and form recesses on the surface. Further, the slurry 18 is dropped from the slurry supply unit 16 onto the surface of the polishing pad 13.

  In the chemical conditioning process, a hydrophilic material such as titanium oxide is applied to the polishing pad 13. Specifically, the nozzle 32 is rotated while the arm portion 31 of the chemical conditioner 15 is swung. In this manner, a hydrophilic material such as titanium oxide is applied to the surface of the polishing pad 13 to form a uniform film of the hydrophilic material on the surface of the polishing pad 13.

  FIG. 4 is a schematic cross-sectional view of the polishing pad 13 in a state in which a titanium oxide film is formed on the surface of the polishing pad 13 and a plane perpendicular to the polishing pad 13. Since the titanium oxide film 43 is highly hydrophilic, a large number of slurry particles 41 in the slurry 18 are held on the surface 44 of the polishing pad as shown in FIG. Even if the sharpening is insufficient and the number of the concave portions 42 formed on the surface 44 of the polishing pad is small, a large number of slurry particles 41 can be held.

  In this way, it is possible to improve the wettability of the polishing pad 13 with the slurry 18 by applying a hydrophilic material. Thereby, the grinding | polishing target object 17 can be grind | polished stably and grinding | polishing efficiency can be improved.

  In the chemical mechanical polishing method of this embodiment, an acidic chemical solution is not used to make the polishing pad hydrophilic. Therefore, rinsing is unnecessary after the polishing pad is made hydrophilic. Furthermore, since the conventional polishing of the dummy wafer is unnecessary, the polishing efficiency is improved.

  Further, since it is unnecessary to rinse the rinse wafer or the dummy wafer, the polishing process, the chemical conditioning process, and the mechanical conditioning process can be performed simultaneously. By carrying out these steps simultaneously, the polishing efficiency and the production efficiency are further improved.

  In addition, the chemical conditioning process can be performed simultaneously with at least the mechanical conditioning process, thereby improving the polishing efficiency.

  As mentioned above, although preferred embodiment of this invention was shown and described in detail, it understands that this invention is not limited to the said Example, A various change and correction are possible unless it deviates from the summary. I want to be.

  For example, as long as the present invention can be implemented, the polishing table 12, the head 11, the mechanical conditioner 14, the chemical conditioner 15, and the like may have any shape. The chemical conditioner 15 may have any form as long as a film of a hydrophilic material can be formed on the surface of the polishing pad 13.

(A) is a typical top view of the chemical mechanical polishing apparatus which concerns on one Embodiment of this invention, (b) It is a typical side view of a chemical mechanical polishing apparatus. (A) is a typical side view of a mechanical conditioner, (b) is a schematic bottom view of a mechanical conditioner. (A) is typical sectional drawing of a chemical conditioner, (b) is a typical bottom view of a chemical conditioner. The figure which shows the mode of the slurry particle hold | maintained on the surface of the polishing pad to which the titanium oxide film was given. (A) is a typical top view of the conventional chemical mechanical polishing apparatus, (b) is a schematic side view of the conventional chemical mechanical polishing apparatus. (A) is a figure which shows the mode of the slurry particle hold | maintained on the surface of the polishing pad with sufficient dressing, (b) is a figure which shows the mode of the slurry particle hold | maintained on the surface of the polishing pad with insufficient dressing It is.

Explanation of symbols

11, 51 Head 12, 52 Polishing table 13, 53 Polishing cloth pad 14, 54 Mechanical conditioner 15 Chemical conditioner 16, 56 Slurry supply unit 17, 57 Polishing target 18, 58 Slurry 21, 31 Arm unit 22 Base Part 23 Abrasive electrodeposition part 32 Nozzle 33 Storage part 34 Channel 35 Outlet 41, 61 Slurry particles 42, 62 Recess 43 Titanium oxide film 44, 64 Surface of polishing pad

Claims (8)

In a chemical mechanical polishing apparatus having a polishing pad for polishing a polishing object and a mechanical conditioner for sharpening the surface of the polishing pad,
The chemical mechanical polishing apparatus further comprising a chemical conditioner for applying a hydrophilic material to a surface of the polishing pad.   2. The chemical mechanical polishing apparatus according to claim 1, wherein the chemical conditioner applies the hydrophilic material to a surface of the polishing pad during polishing of the object to be polished. The chemical conditioner has an outflow surface through which the hydrophilic material installed facing the polishing pad flows out,
The chemical mechanical polishing apparatus according to claim 1, wherein the outflow surface rotates during application of the hydrophilic material. The chemical conditioner is swingably supported,
The chemical mechanical polishing apparatus according to any one of claims 1 to 3, wherein the chemical mechanical polishing apparatus swings during application of the hydrophilic material.   The chemical mechanical polishing apparatus according to claim 1, wherein the hydrophilic material is titanium oxide. A holding step for holding the object to be polished against the polishing pad;
A polishing step of polishing the polishing object with a polishing pad;
Mechanical conditioning step of sharpening the surface of the polishing pad and dropping slurry onto the polishing pad;
A chemical conditioning step of applying a hydrophilic material to the surface of the polishing pad.   7. The chemical mechanical polishing method according to claim 6, wherein at least the mechanical conditioning step and the chemical conditioning step are performed simultaneously.   The chemical mechanical polishing method according to claim 6, wherein the polishing step, the mechanical conditioning step, and the chemical conditioning step are performed simultaneously.

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