Chemical mechanical polishing conditioner

Provided is a CMP conditioner comprising: a substrate, multiple abrasive bars, and multiple slide blocks. The substrate is divided into a central surface and an outer surface. The central surface is a recessed part. The outer surface encompasses the central surface. Multiple mounting holes are recessed from the outer surface. The abrasive bars are each respectively mounted in the mounting holes. Each of the multiple abrasive bars comprises a bar body and an abrasive particle. The abrasive particle is mounted on a top surface of the abrasive bar. The multiple slide blocks are distributed among the mounting holes of the outer surface. Each of the multiple slide blocks comprises a slide dressing surface. The present invention utilizes the slide blocks to reduce the contact between the substrate and a polishing mat efficiently. The slide blocks may decrease dissolving out of metal components within the substrate and the pollution induced.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a chemical mechanical polishing (CMP) conditioner, and more particularly to a CMP conditioner comprising slide blocks.

2. Description of the Related Art

CMP is a planarization technique used in various processes. Because CMP is suitable for large scale planarization, CMP is widely applied to planarization of silicon surfaces or copper surfaces after stacking of integrated circuits.

An apparatus of CMP usually comprises a polishing pad and a CMP conditioner. During a CMP process, a slurry is supplied on the polishing pad by spin coating, and then a surface of an article to be polished is pressed against the polishing pad to polish the surface of the article. The surface of the article is planarized by the grinding and polishing process with the polishing pad.

However, scraps produced during the polishing process accumulate and stagnate in holes of the polishing pad, forming a hardened layer. The hardened layer decreases the polishing efficiency of the polishing pad and shortens the lifetime of the polishing pad. Therefore, the CMP conditioner is used during the CMP process to dress the surface of the polishing pad, so as to prolong the life time of the polishing pad.

In view of the abovementioned problem, patent application TW 103202785 discloses a CMP conditioner. Abrasive particles in the CMP conditioner each comprises a specific orientation of tip, a specific height of tip, or a specific dressing angle to achieve the best grinding performance. However, the abrasive particles81of the CMP conditioner8protruding into the polishing pad are deeper during the polishing process with reference toFIG. 8. The slurry in contact with the substrate82then induces the corrosion easily. The metal components within the substrate82may be dissolved out and then stagnate on the polishing pad9. Wafers may be polluted by the metal components within the substrate82on the polishing pad9indirectly during the polishing process. Therefore, the structures of the conventional CMP conditioner still need to be improved.

SUMMARY OF THE INVENTION

The present invention ameliorates the CMP conditioner with structures in the prior art to reduce chances of contact between the substrate and the polishing pad, thereby decreasing dissolving out of metal components within the substrate and their stagnation on the polishing pad, which directly induces the pollution of the wafers during the polishing process.

The present invention provides a CMP conditioner comprising:

a substrate being circular and comprising a central surface, an outer surface encompassing the central surface, and multiple mounting holes recessed from the outer surface;

multiple abrasive bars respectively mounted in the mounting holes; each of the multiple abrasive bars comprising a bar body and an abrasive particle, the bar body comprising a top surface; the abrasive particle comprising a tip; the abrasive particle mounted on the top surface with the tip pointing away from the top surface; and

multiple slide blocks mounted on the outer surface; each of the multiple slide blocks comprising a slide dressing surface facing away from the outer surface; the multiple slide blocks distributed among the mounting holes.

The CMP conditioner of the present invention may decrease contact between the polishing pad and the substrate by the slide blocks effectively. Furthermore, the corrosion of the substrate by the slurry also decreases and the metal components within the substrate may not dissolve out and stagnate on the polishing pad to pollute the wafers indirectly. In addition, the working area of the abrasive bars distributed on the outer surface is wide. The removing effect of the abrasive bars is uniform, and the efficiency of the abrasive bars is excellent.

Preferably, the straight distances between each of the multiple mounting holes and a center of the central surface are different. The distances between any two neighbors of the multiple mounting holes are different. This prevents the shadow effect occurring in the polishing process to the CMP conditioner.

Preferably, the substrate is made of stainless steel, ceramics, or engineering plastic. The bar body is made of stainless steel. The abrasive particles are artificial diamond, natural diamond, polycrystalline diamond, or cubic boron nitride. More preferably, the abrasive particles are applied by a surface treatment. The abrasive particles comprise specific dressing angles, specific crystal structures, or directionalities of tip to achieve the best polishing performance.

Preferably, the tip protrudes from the outer surface. The top surface is higher than the outer surface, or the top surface is lower than the outer surface.

Preferably, a height of the slide dressing surface is between the tip and the top surface or a height of the slide dressing surface is equal to a height of the tip.

Preferably, the multiple mounting notches are recessed from the outer surface. The mounting notches are distributed among the mounting holes. Each of the multiple slide blocks is correspondingly mounted in each of the multiple mounting notches. More preferably, the multiple slide blocks are arranged in a cross pattern, a radial pattern, or an asterisk pattern. In addition, the multiple slide blocks and the substrate are integrated.

Preferably, 5% to 25% of an area of the outer surface is occupied by the multiple slide blocks. If less than 5% of the outer surface is occupied by the multiple slide blocks, the multiple slide blocks may not be used as a cushion between the polishing mat and the substrate effectively. If larger than 25% of the outer surface is occupied by the multiple slide blocks, the space provided for mounting the abrasive bars may be reduced.

Preferably, an area of the central surface is 40% to 80% of the total area of the central surface and the outer surface. An area of the outer surface is 20% to 60% of the total area of the central surface and the outer surface. A vertical distance between the tip and the outer surface is 0.12 to 4.15 mm. A height difference between the height of the slide dressing surface and the height of the tip is 0.02 to 0.15 mm. A vertical distance between the height of the slide dressing surface and the height of the outer surface is 0.1 to 4 mm. If the vertical distance between the height of the slide dressing surface and the height of the outer surface is larger than 5 mm, the thickness of the CMP conditioner is too large and increases the cost of the CMP conditioner. Furthermore, it is easy to induce falling off of the abrasive bars if the abrasive bars are too much exposed on the substrate.

Preferably, the surface structure of the slide dressing surface is a smooth surface. If the surface structure of the slide dressing surface is a non-smooth surface, the non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. Preferably, a shape of each of the multiple slide blocks is circular, elliptical, polygonal, elongated, helical or fan-shaped.

Preferably, each of the slide dressing surfaces is consisting of cemented materials, noble metals, cubic boron nitride, sapphire, hard ceramic, diamond, diamond like carbon or engineering plastic. More preferably, the cemented materials comprise silicon carbide, tungsten carbide, or molybdenum carbide. The noble metals comprise gold, silver, titanium alloy, platinum-iridium alloy, thallium, or vanadium.

More preferably, each of the slide dressing surfaces is plated with a layer of diamond film.

In addition, the multiple slide blocks comprise first slide blocks and second slide blocks. The first slide blocks and the second slide blocks are arranged alternatively along the outer surface. Each of the first slide blocks comprises a first slide dressing surface away from the outer surface, and a surface structure of the first slide dressing surface is a non-smooth surface. The non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. A height of the first slide dressing surface is between a height of the tip and a height of the top surface. Each of the second slide blocks comprises a second slide dressing surface away from the outer surface, and a surface structure of the second slide dressing surface is a non-smooth surface. The non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. A height of the second slide dressing surface is between a height of the tip and a height of the top surface.

Preferably, a height of the first slide dressing surface is equal to a height of the second slide dressing surface or the height of the first slide dressing surface differs from the height of the second slide dressing surface. Preferably, a height of the second slide dressing surface is relatively lower than a height of the first slide dressing surface. A height difference between each of the height of the first slide dressing surface and each of the height of the second slide dressing surface is 20 to 50 μm.

Preferably, the shapes of the first slide blocks and the second slide blocks are circular, elliptical, polygonal, elongated, helical or fan-shaped.

Preferably, each of the second slide dressing surfaces is consisting of cemented materials, noble metals, cubic boron nitride, sapphire, hard ceramic, diamond, diamond like carbon or engineering plastic. More preferably, the cemented materials comprise silicon carbide, tungsten carbide, or molybdenum carbide. The noble metals comprise gold, silver, titanium alloy, platinum-iridium alloy, thallium, or vanadium.

More preferably, the second slide dressing surfaces are plated with a layer of diamond film.

The height of the second slide dressing surface is between the height of the tip and the height of the top surface. In other words, a protruding depth of the second slide dressing surface into the polishing mat is small than the height of the tip of the abrasive particles in the polishing process. The over coarsened parts of the polishing mat on its surface may be smoothened by the second slide dressing surface after the polishing process by abrasive particles. Furthermore, the height of the second slide dressing surface differs from the height of the first slide dressing surface. It is effective to help users to control the roughness of the surface with the polishing mat.

In addition, the multiple slide blocks comprise first slide blocks and second slide blocks. The first slide blocks and the second slide blocks are arranged alternatively along the outer surface. Each of the first slide blocks comprises a first slide dressing surface away from the outer surface, and a surface structure of the first slide dressing surface is a smooth surface. A height of the first slide dressing surface is between a height of the tip and a height of the top surface. Each of the second slide blocks comprises a second slide dressing surface away from the outer surface, and a surface structure of the second slide dressing surface is a non-smooth surface. The non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. A height of the second slide dressing surface is between a height of the tip and a height of the top surface. A height of the first slide dressing surface is relatively lower than a height of the second slide dressing surface. A difference in vertical distance between each of the heights of the first slide dressing surfaces and each of the heights of the second slide dressing surfaces is 30 to 70 μm.

DETAILED DESCRIPTION OF THE INVENTION

With reference toFIGS. 1 and 2, a first embodiment of the present invention provides a CMP conditioner1comprising a substrate10, multiple abrasive bars20, and multiple slide blocks30.

The substrate10is circular and comprises a surface. The surface is defined into a central surface11and an outer surface12. The central surface11and the outer surface12are concentric. A concave part is formed in the central surface11of the surface. The outer surface12encompasses the central surface11. Multiple mounting holes13and multiple mounting notches14are recessed in the outer surface12of the surface. The multiple mounting notches14are distributed among the multiple mounting holes13. A sectional difference between the concave part and the outer surface12is 0.5 mm. A thickness D1of the substrate10is 4 mm. Based on a total area of the central surface11and the outer surface12, an area of the central surface11is 80% of the total area and an area of the outer surface12is 20% of the total area. Based on the area of the outer surface12, an area of the multiple mounting holes13is 10% of the area of the outer surface12. The substrate10is made of stainless steel. The straight distances between each of the multiple mounting holes13and a center of the central surface11are different. The distances between any two adjacent mounting holes13are different.

Each of the multiple abrasive bars20is correspondingly mounted in each of the multiple mounting holes13. Each of the multiple abrasive bars20comprises a bar body21and an abrasive particle22. The abrasive particle22is mounted with the bar body21. The bar body21further comprises a top surface211. A level of the top surface211is higher than a level of the outer surface12. The abrasive particle22is mounted on the top surface211. The abrasive particle22further comprises a tip221, and the tip221is away from the top surface211. A vertical distance D2between the tip221and the outer surface12is 0.12 mm. The bar body21is made of stainless steel. The abrasive particle22is natural diamond.

Each of the multiple slide blocks30is corresponding to and mounted in the above-said multiple mounting notches14. Specifically, the multiple slide blocks30are arranged in a cross pattern along the outer surface12. The shape of each of the multiple slide blocks30is elongated. Each of the multiple slide blocks30comprises a slide dressing surface away from the outer surface12. Specifically, the multiple slide blocks30are the first slide blocks31. The slide dressing surface of the first slide block31is a first slide dressing surface311. A surface structure of the first slide dressing surface311is a smooth surface. A height of the first slide dressing surface311(which means a vertical distance between the first slide dressing surface311and the outer surface12) is between a height of the tip221(which means a vertical distance between the tip221and the outer surface12) and a height of the outer surface12(which means a vertical distance between the top surface211and the outer surface12). A height difference D3between the height of the first slide dressing surface311and the height of the tip221is 0.02 mm. A vertical distance D4between the height of the first slide dressing surface311and the height of the outer surface12is 0.1 mm. Based on the area of the outer surface12, an area of the first slide dressing surface311occupied by the first slide blocks31is 5% of the area of the outer surface12. A material of the first slide blocks31includes silicon carbide. The first slide dressing surface311is plated with a layer of diamond film.

With reference toFIGS. 3 and 4, a second embodiment of the present invention provides a CMP conditioner1A. The CMP conditioner1A is similar to the CMP conditioner1. The difference between the CMP conditioner1A and the CMP conditioner1is that multiple mounting notches14A are arranged in a radial pattern along the outer surface12. A sectional difference D5between the concave part and the outer surface12A is 1 mm. The thickness D1of the substrate10A is 5.25 mm. Based on a total area of the central surface11A and the outer surface12A, an area of the central surface11A is 64% of the total area and an area of the outer surface12A is 36% of the total area. Based on the area of the outer surface12A, an area of the multiple mounting holes13A is 31% of the area of the outer surface12A. The substrate10A is made of ceramics.

A vertical distance D2between the tip221A and the outer surface12A is 0.25 mm. The abrasive particle22A is cubic boron nitride.

Each of the multiple slide blocks30A is a second slide block32A. Each of the multiple slide blocks30A comprises a slide dressing surface away from the outer surface12A. The slide dressing surface of the second slide block32A is a second slide dressing surface321A. A surface structure of the second slide dressing surface321A is a non-smooth surface. The non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. A height of the second slide dressing surface321A (which means a vertical distance between the second slide dressing surface321A and the outer surface12A) is between a height of the tip221A and a height of the top surface211A. A height difference D6between the height of the second slide dressing surface321A and the height of the tip221A is 0.05 mm. A vertical distance D7between the height of the second slide dressing surface321A and the height of the outer surface12A is 0.2 mm. Based on the area of the outer surface12A, an area of the second slide block32A is 10.8% of the area of the outer surface12A. A material of the second slide blocks32A includes cubic boron nitride. The second slide dressing surface321A is plated with a layer of diamond film.

With reference toFIGS. 5 and 6, a third embodiment of the present invention provides a CMP conditioner1B. The CMP conditioner1B is similar to the CMP conditioner1. The difference between the CMP conditioner1B and the CMP conditioner1is that a sectional difference between the concave part and the outer surface12B is 3 mm. The thickness D1of the substrate10B is 7 mm. Based on a total area of the central surface11B and the outer surface12B, an area of the central surface11B is 40% of the total area and an area of the outer surface12B is 60% of the total area. Based on the area of the outer surface12B, an area of the multiple mounting holes13B is 50% of the area of the outer surface12B. The substrate10B is made of engineering plastic.

A vertical distance between the tip and the outer surface12B is 4.15 mm.

The multiple slide blocks30B are arranged in an asterisk pattern along the outer surface12B. The multiple slide blocks30B are divided into first slide blocks31B and second slide blocks32B. The first slide blocks31B and the second slide blocks32B are circular. The first slide blocks31B and the second slide blocks32B are arranged alternatively along the outer surface12B. Each of the first slide blocks31B comprises a first slide dressing surface311B away from the outer surface12B. A surface structure of the first slide dressing surface311B is a smooth surface. A height of the first slide dressing surface311B is between a height of the tip and a height of the top surface. Each of the second slide blocks32B comprises a second slide dressing surface321B away from the outer surface12B. A surface structure of the second slide dressing surface321B is a non-smooth surface. The non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. A height of the second slide dressing surface321B is between a height of the tip and a height of the top surface. A height difference between the height of the second slide dressing surface321B and the height of the tip is 0.15 mm. A vertical distance D7between the height of the second slide dressing surface321B and the height of the outer surface12B is 4 mm. A height of each of the first slide dressing surfaces311B is relatively lower than a height of each of the second slide dressing surfaces321B. A height difference D8between the height of the first slide dressing surface311B and the height of the second slide dressing surface321B is 50 μm. Based on the area of the outer surface12B, a total area of an area of the second slide blocks32B and an area of the first slide blocks31B is 25% of the area of the outer surface12B. A material of the first slide blocks31B includes sapphire. A material of the second slide blocks32B includes hard ceramics.

With reference toFIG. 7, a fourth embodiment of the present invention provides a CMP conditioner1C. The CMP conditioner1C is similar to the CMP conditioner1. The difference between the CMP conditioner1C and the CMP conditioner1is that the substrate10C is made of engineering plastic. The multiple slide blocks30C are also made of engineering plastic. The multiple slide blocks30C and the substrate10C are integrated. The multiple slide blocks30C are divided into first slide blocks31C and second slide blocks32C. The first slide blocks31C and the second slide blocks32C are arranged alternatively along the outer surface12C. Each of the first slide blocks31C comprises a first slide dressing surface311C away from the outer surface12C. A surface structure of the first slide dressing surface311C is a non-smooth surface. The non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. A height of the first slide dressing surface311CB is between a height of the tip and a height of the top surface. Each of the second slide blocks32C comprises a second slide dressing surface321C away from the outer surface12C. A surface structure of the second slide dressing surface321C is a non-smooth surface. The non-smooth surface comprises multiple microstructures including multiple concave parts and convex parts. A height of the second slide dressing surface321C (which means a vertical distance between the second slide dressing surface321C and the outer surface12C) is between a height of the tip and a height of the top surface. A height difference between the height of the first slide dressing surface311C and the height of the tip is 0.15 mm. A vertical distance D7between the height of the first slide dressing surface311C and the height of the outer surface12C is 4 mm. A height of each of the second slide dressing surfaces321C is relatively lower than a height of each of the first slide dressing surfaces311C. A height difference D9between the height of the second slide dressing surface321C and the height of the first slide dressing surface311C is 35 μm. Based on the area of the outer surface12C, a total area of an area of the first slide blocks31C and an area of the second slide blocks32C is 25% of the area of the outer surface12C.

When the CMP conditioner1C is used as a polishing mat, the abrasive particles are used to polish a surface of the polishing mat. The polishing mat may maintain a specific roughness of the surface with the polishing mat. The height of the first slide dressing surface311C and the height of the second slide dressing surface321C are between the height of the tip and the height of the top surface. This means the tip protruding into the polishing mat is deeper than the first slide dressing surface311C and the second slide dressing surface321C in the polishing process. The surface of the polishing mat is over coarse. If the tip acts in concert with the first slide dressing surface311C and the second slide dressing surface321C that may protrude into the polishing deeper, the CMP conditioner1C may remove protrusions on the surface of the polishing mat and smoothen the surface of the polishing mat. It is effective to reduce the roughness of the surface with the polishing mat.

Comparative Example

A CMP conditioner8in this comparative example is similar to the CMP conditioner1in the embodiment 1. The difference between the CMP conditioner8and the CMP conditioner1is that the CMP conditioner8has no slide block.

Testing

With reference toFIGS. 9 and 11, a red color layer was coated on an outer surface of the CMP conditioner8in the comparative example and an outer surface of the CMP conditioner1in embodiment 1 respectively. Then the CMP conditioner8and the CMP conditioner1were used to polish the polishing mat respectively. The pressure applied on the CMP conditioner8and the CMP conditioner1was 3.5 kg. The results are shown in theFIGS. 9 to 12.

With reference toFIGS. 9 and 10, the red color layer on the outer surface of the CMP conditioner8in the comparative example disappeared after the polishing process. Slurry was in contact with the outer surface of the CMP conditioner8continuously, and the red color layer was washed away by the slurry in the polishing process. With reference toFIGS. 11 and 12, the red color layer on the outer surface12of the CMP conditioner1in the embodiment 1 was similar as before. The slide blocks30were used to reduce the contact between the outer surface of the CMP conditioner1and the polishing mat in the polishing process. Accordingly,FIG. 12show no color loss due to reduction of contact.

The CMP conditioner of the present invention utilizes the slide blocks to reduce the contact between the substrate of the CMP conditioner and the polishing mat efficiently. The slide blocks may also prevent the pollution to the polishing mat and wafer by the metal ions from the slurry.