JP2010207943A - Cmp conditioner and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a CMP conditioner capable of prolonging the service life of a CMP pad that is an object to be polished while keeping the surface state of the CMP pad constant, and the method for manufacturing the CMP conditioner. <P>SOLUTION: The CMP conditioner grinds the CMP pad using a cutting edges 5 protruded from the surface of a mound 4 of a base plate. As a cutting edge, the cutting edge 5 has a convex curved-shape that is formed to be a protruded cross-sectional circular arc and the surface thereof is reinforced by a carbon-based thin film 5a. The cutting edge having the convex curved-shape is formed semispherical with an average curvature radius set to 0.02-0.5 mm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a CMP conditioner used for conditioning a CMP pad of a semiconductor polishing apparatus that polishes a semiconductor wafer or the like, and a method for manufacturing the CMP conditioner.

  In recent years, with the progress of the semiconductor industry, there is an increasing need for processing methods for finishing surfaces of metals, semiconductors, ceramics, etc. with high precision. It is requested. In order to cope with such a high-precision surface finish, CMP (chemical mechanical polishing) polishing using a porous CMP pad is generally performed on a semiconductor wafer.

  A CMP pad used for polishing a semiconductor wafer or the like causes clogging or compression deformation as the polishing time elapses, and its surface state gradually changes. Then, since undesired phenomena such as a decrease in polishing rate and non-uniform polishing occur, by using a CMP pad conditioner and periodically grinding the surface of the CMP pad, the surface state of the CMP pad is kept constant, A device for maintaining a good polishing state for a semiconductor wafer or the like has been devised.

As an example of a CMP pad conditioner used for grinding a CMP pad, those disclosed in Patent Documents 1 and 2 are known.
In the CMP pad conditioner of Patent Document 1, superabrasive grains (cutting blades) having sharp edges on a plurality of protrusions (mounds) formed on the surface of a substrate are dispersed and fixed by a metal plating phase. The top surface portion of the grain is pressed against the CMP pad and ground, so that the surface state of the CMP pad is kept constant.
Further, in the CMP pad conditioner of Patent Document 2, superabrasive grains having sharp edges on the surface are plated with metal on ring-shaped ridges and a plurality of ridges distributed inside the ring-shaped ridges. The top surface portion of the superabrasive grains is pressed against the CMP pad and ground to maintain a constant surface state of the CMP pad.

JP 2001-712263 A JP 2002-337050 A

  In the CMP pad conditioner described in Patent Documents 1 and 2, the surface of the CMP pad is formed by cutting blades made of superabrasive grains dispersed and fixed to a plurality of protrusions or ring-shaped ridges formed on the substrate. The surface state of the CMP pad is kept constant by fuzzing at the same time. In this way, the surface of the CMP pad that is the object of grinding is basically scraped off by superabrasive grains having sharp edges, so that the surface state is kept constant. There was a problem.

  The present invention has been made in view of the above-described circumstances, and is a CMP conditioner and a CMP conditioner capable of extending the life of the CMP pad while keeping the surface state of the CMP pad to be ground constant. The manufacturing method of this is provided.

In order to solve the above problems, the present invention proposes the following means.
In other words, the CMP conditioner of the present invention is a CMP conditioner that uses a cutting blade protruding from the surface of the substrate to grind the CMP pad disposed opposite to the substrate, and forms a cross-sectional arc as the cutting blade. It has a convex curved cutting edge which is formed in a convex shape and whose surface is reinforced with a carbon-based thin film.

According to the CMP conditioner configured as described above, it has a convex curved cutting edge formed in a convex shape having a cross-sectional arc without having a sharp edge portion, and this convex curved cutting blade is to be ground. When contacting the CMP pad, the surface of the CMP pad is kept constant by mainly removing the clogging without scraping off the contact surface of the CMP pad.
That is, the grinding amount of the CMP pad is reduced as compared with the grinding process using the cutting edge made of superabrasive grains having sharp edges as described in the background art.
Further, since the surface of the convex curved cutting edge is reinforced with a carbon-based thin film, the amount of wear of the convex curved cutting edge itself is reduced when contacting the CMP pad.

The cutting blade is preferably formed on the surface of the mound protruding upward from the substrate body.
In this case, the part where the mound is not formed on the substrate body is not formed with a cutting edge and is one step lower than the surface of the mound, and this part is used as a discharge passage for chips and the like to the CMP pad. The contained chips and slurry can be discharged to the outside. For this reason, clogging of the CMP pad conditioner can be quickly eliminated. In addition, since the cutting blade is provided on the mound that protrudes upward from the substrate body, compared to the case where the cutting blade is provided on the substrate body that is flush with no mound, the cutting pad is relatively soft. When contacting, the cutting blade can be prevented from being solid, and the contact pressure of the cutting blade against the CMP pad can be set high.

The convex curved cutting edge is preferably formed in a hemispherical shape with a radius of curvature set to 0.02 to 0.5 mm.
In this case, since the cutting edge is appropriately sized, it is possible to ensure a good balance between maintaining a small amount of grinding when grinding the CMP pad and obtaining good discharge of chips and slurry. .

It is preferable that all the cutting blades are constituted by the convex curved cutting blades.
In this case, since all the cutting edges are formed by convex curved cutting edges, the amount of grinding when grinding the CMP pad can be further reduced.

  In the CMP conditioner manufacturing method of the present invention, the CMP conditioner manufacturing method according to any one of claims 1 to 4, wherein the convex curved cutting edge is obtained by performing laser processing on the surface of the substrate. A convex forming step for forming a convex shape having a cross-sectional arc, and a thin film forming step for forming a carbon-based thin film on at least the convex surface having the cross-sectional arc by a vapor phase synthesis method.

In the above-described CMP conditioner manufacturing method, even if the substrate is made of a ceramic material such as SiC or Si ₃ N ₄ , laser processing is employed, so that it can be easily formed into an arbitrary shape so as to form a convex shape having a circular arc in cross section. Can be processed. In addition, since the carbon-based thin film is formed by the vapor phase synthesis method, a thin film having a substantially uniform thickness can be formed on the convex surface serving as the convex curved cutting edge.

  According to the present invention, when the CMP pad is ground, the clogging is mainly eliminated without removing the contact surface of the CMP pad so much, and the surface state of the CMP pad can be kept constant. The life of the pad can be extended. In addition, since the amount of wear of the convex curved cutting edge itself is reduced, the life of the CMP pad conditioner itself can be extended.

It is a top view of CMP pad conditioner of an embodiment of the present invention. It is a front view of CMP pad conditioner of an embodiment of the present invention. It is an enlarged view of the III circle part of FIG. FIG. 4 is a partial cross-sectional view in which an IV circle portion in FIG. 2 is enlarged.

A CMP pad conditioner according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a plan view of a CMP pad conditioner, and FIG. 2 is a front view of the CMP pad conditioner.
As shown in these drawings, the CMP pad conditioner 1 has a substantially disk shape and has a substrate 2 that rotates around a central axis (not shown). The substrate 2 is made of a ceramic material such as silicon carbide (SiC) or silicon nitride (Si ₃ N ₄ ).
The substrate 2 includes a disk-shaped substrate body 3 and a mound 4 formed to protrude outwardly on one surface of the substrate body 3. A cutting blade 5 is formed on the mound 4 as shown in FIGS.

  The mound 4 is formed one step higher than the other part of the substrate 2, and is formed in a truncated cone shape, for example. The height H of the mound 4 is set to 0.5 to 300 μm, and the radius L is set to about 0.5 to 3 mm. Further, although only nine mounds 4 are shown in FIG. 1 for ease of viewing in FIG. 1, actually, for example, when the substrate 2 is 4 inches, about 100 to 200 are formed.

  A cutting blade 5 is formed on the mound 4 as shown in FIGS. In the case of this illustrated example, the cutting blades 5 are all composed of hemispherical convex curved cutting blades having a radius l set to 0.02 to 0.5 mm, for example. Further, for example, about 1 to 20 cutting edges 5 are formed on one mound 4.

  A carbon-based thin film 5a such as a diamond thin film is formed on the surface of the cutting blade 5, and the cutting blade 5 is reinforced by this. Note that the carbon-based thin film 5a only needs to be formed at least in a portion to be the cutting edge 5, and does not need to be formed to other portions. The film thickness of the carbon-based thin film 5a is set to about 3 to 20 μm.

  The shape of the cutting blade 5 is hemispherical in the figure, but is not limited to this, and the top portion forms a cross-sectional arc and the skirt portion gradually expands outward. Alternatively, the egg may have a semi-elliptical cross section obtained by cutting the egg in half along the longitudinal direction. It is sufficient if it is formed in a convex shape.

Next, a method for manufacturing the CMP pad conditioner 1 will be described.
First, the substrate 2 is prepared. A mound 4 is formed on the substrate 2. The mound 4 may be formed integrally with the substrate body 3 at the time of molding, or may be formed separately from the substrate body 3, and an adhesive in a later process. It may be attached to the substrate body 3 by appropriate fixing means such as. Furthermore, as will be described later, the mound 4 may be formed at the same time when the portion to be the cutting edge 5 is formed by laser processing.

  Next, the other part is cut by laser scanning using the third harmonic of the YAG laser so that the part that becomes the cutting edge 5 remains in the mound 4 in a hemispherical shape (convex shape forming step). .

Next, a carbon-based thin film 5a is formed on the surface of the portion to be the cutting edge 5 by a CVD method using a reaction vessel composed of a gas phase synthesis method hot filament furnace (thin film forming step). Specifically, in the reaction vessel, the methane (CH ₄ ) concentration is set to about 1%, and a diamond thin film is formed on the portion that becomes the cutting edge 5 in this environment.
Since the carbon-based thin film 5a only needs to be formed in a portion to be the cutting edge 5, masking is performed on other portions on the substrate 2, and a carbon-based thin film 5a of a portion different from the cutting blade 5 is formed in a later process. It may be removed together with the mask. Further, if it is more troublesome to form the carbon-based thin film 5a only on the portion that becomes the cutting edge 5, the carbon-based thin film 5a may be formed on one side of the mound 4 or on one side of the substrate 2.

According to the CMP pad conditioner 1 having the above-described configuration, the cutting blade is formed in a convex shape having an arc of a cross section without having a sharp edge portion. The surface state of the CMP pad can be kept constant by mainly removing only the clogging without scraping off the contact surface. For this reason, the lifetime of a relatively expensive CMP pad can be extended.
Further, since the surface of the cutting blade 5 is reinforced by the carbon-based thin film 5a, the amount of wear of the cutting blade 5 itself can be reduced when contacting the CMP pad.
Further, since the cutting edge 5 is formed in a hemispherical shape, there is no directivity in grinding the CPM pad, and uniform grinding can be performed in all directions.

  Further, the cutting blade 5 is formed on a disk-shaped mound 4 protruding upward from the substrate body 3, and the portion of the substrate body 3 where the mound 4 is not formed is not formed with the cutting blade 5. Moreover, it is one step lower than the surface of the mound 4, and this location can be used as a discharge passage. That is, by using this portion, chips and slurry contained in the CMP pad can be positively discharged to the outside, and the chip and the like are excellent in discharging properties. For this reason, clogging of the CMP pad conditioner can be quickly eliminated.

  In addition, since the cutting blade 5 is provided on the mound 4 protruding upward from the substrate body 3, it is relatively soft as compared with the case where the cutting blade 5 is provided on the substrate body 3 that is flush with the mound. Also when contacting the CMP pad, the cutting blade 5 can be prevented from being solid and the contact pressure of the cutting blade 5 with respect to the CMP pad can be set high.

Further, since the cutting edge 5 is formed in a convex shape with a radius of curvature set to 0.02 to 0.5 mm, it is possible to keep the amount of grinding when grinding the CMP pad small, as well as chips and slurry. Both sides of obtaining good discharge can be secured in a balanced manner.
That is, when the top of the cutting edge 5 is formed in a hemispherical shape with a radius of curvature of less than 0.02 mm, it has the same meaning as the cutting edge 5 having a sharp edge, and when the CMP pad is ground. In addition, the grinding amount of the CMP pad increases. On the other hand, when the cutting blade 5 is formed in a hemispherical shape with a radius of curvature exceeding 0.5 mm, the top of each cutting blade 5 becomes too smooth, and there is a risk that chips and slurry cannot be discharged well. .

As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, this invention is not limited to these embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.
For example, in the above-described embodiment, the example in which the substrate 2 is formed of silicon carbide (SiC) or silicon nitride (Si ₃ N ₄ ) is shown, but the present invention is not limited to this, and the substrate 2 may be formed of other ceramic materials. good.

Moreover, in the said embodiment, although all the cutting blades 5 are comprised by the convex-curved cutting blade, it is not restricted to this, It consists of the superabrasive grain generally used conventionally with one CMP pad conditioner. You may use together a cutting blade and the convex-curved cutting blade which is the characteristic component of this invention. In this case, it is sufficient that the ratio between the cutting edge made of superabrasive grains and the convex-curved cutting edge is appropriately determined according to the purpose of use and conditions of use.
Moreover, in the said embodiment, although the mound 4 was made into truncated cone shape, it is not restricted to this, It is good also as disk shape, elliptical shape, or polygonal shape.
Moreover, although the example which forms a diamond thin film on the surface of the cutting blade 5 was shown in the said embodiment, it is not restricted to this, For example, you may comprise the carbon-type thin film 5a by DLC etc.

1 CMP pad conditioner 2 Substrate 3 Substrate body 4 Mound 5 Cutting blade (convex curved cutting blade)
5a Carbon thin film

Claims (5)

A CMP conditioner that uses a cutting blade protruding from the surface of the substrate to grind the CMP pad disposed opposite to the substrate,
A CMP conditioner comprising: a convex curved cutting blade which is formed in a convex shape having a circular arc in cross section and whose surface is reinforced with a carbon-based thin film as the cutting blade.   The CMP conditioner according to claim 1, wherein the cutting blade is formed on a surface of a mound protruding upward from the substrate body.   3. The CMP conditioner according to claim 1, wherein the convex curved cutting edge is formed in a hemispherical shape having an average curvature radius of 0.02 to 0.5 mm.   The CMP conditioner according to any one of claims 1 to 3, wherein the cutting blades are all constituted by the convex curved cutting blades. It is a manufacturing method of CMP conditioner given in any 1 paragraph of Claims 1-4,
A convex forming step of forming a convex shape having a cross-sectional arc to be the convex curved cutting edge by performing laser processing on the surface of the substrate;
A CMP conditioner manufacturing method comprising: a thin film forming step of forming a carbon-based thin film on at least a convex surface having a circular arc in cross section by a vapor phase synthesis method.

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