US20070128991A1

US20070128991A1 - Fixed abrasive polishing pad, method of preparing the same, and chemical mechanical polishing apparatus including the same

Info

Publication number: US20070128991A1
Application number: US11/634,195
Authority: US
Inventors: Il-young Yoon; Hong-jae Shin; Se-young Lee; Jae-ouk Choo; Ja-Eung Koo
Original assignee: Samsung Electronics Co Ltd
Current assignee: Samsung Electronics Co Ltd
Priority date: 2005-12-07
Filing date: 2006-12-06
Publication date: 2007-06-07

Abstract

A fixed abrasive polishing pad includes a base and a plurality of polishing layers on the base, wherein each polishing layer includes abrasive particles and apertures in a polishing surface of the polishing layer.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates to an apparatus for manufacturing a semiconductor device. More particularly, the present invention relates to a fixed abrasive polishing pad, a method of preparing the same, and chemical mechanical polishing (CMP) apparatus including the same.
2. Description of the Related Art
CMP is a process for planarizing a surface of a substrate, e.g., a semiconductor wafer, which may include a variety of structures, films, etc. formed thereon. CMP effects planarization by combining a mechanical polishing effect with a chemical reaction effect. The mechanical polishing typically involves the application of an abrasive to the wafer surface. The chemical reaction typically involves the application of a reactant solution, e.g., an acidic or basic solution, to the wafer. CMP is a planarization process frequently employed for removing protrusions from a wafer surface, and is very important to the manufacture of semiconductor devices, particularly those having fine multi-layered wiring structures.
A typical CMP apparatus may include a polishing head, which rotates while pressing an elastic polishing pad against a wafer, a pad conditioner for maintaining the polishing pad in a desired state, and an apparatus for supplying a polishing slurry, i.e., a polishing solution. In some applications, the slurry may include an abrasive and/or a reactive solution, e.g., an acidic or basic solution. When the wafer is pressed by the polishing pad while the slurry is being supplied thereto, the acidic or basic solution chemically reacts with the surface of the wafer while the surface of the wafer is mechanically polished by the abrasive to reduce or eliminate uneven surface features. In other applications, the CMP apparatus may use a fixed abrasive polishing pad, in which an abrasive is incorporated into the polishing pad. This CMP apparatus may be used to planarize, e.g., a shallow trench isolation (STI) film.
FIG. 1 illustrates photographically an upper surface of a conventional fixed abrasive polishing pad, and FIGS. 2A and 2B are magnified portions of a polishing layer of the polishing pad of FIG. 1. Referring to FIG. 1, the fixed abrasive polishing pad has a plurality of hexagonal polishing layers PL arranged thereon. The polishing layers PL include abrasive particles. For example, ceria (CeO₂) particles may be used for CMP of an STI film.
Those skilled in the art of CMP will appreciate that there is a high demand for polishing apparatuses capable of providing uniformly planar and defect-free results across very large surfaces. As illustrated in FIGS. 2A and 2B, the conventional CMP fixed abrasive polishing pad utilizes polishing layers PL having smooth surfaces that are free of lumps or holes.
FIG. 3 illustrates a graph of results of a polishing operation performed using a chemical mechanical polishing (CMP) apparatus including the conventional fixed abrasive polishing pad of FIG. 1. In particular, the results were obtained by forming a nitride film hard mask on a wafer, which was etched to a shallow depth using the nitride film as an etch mask. An oxide film was deposited on the etched wafer, thereby forming an STI oxide film. Thereafter, the STI oxide film was subjected to CMP using the polishing pad of FIG. 1.
Referring to FIG. 3, the etch rate RR of the STI oxide film at the center of the wafer (0 on the x-axis) is significantly less than the etch rate RR of the STI oxide film at the edges of the wafer. As a result, the oxide film overlying the nitride film at the center of the wafer is not effectively removed.
One approach to solving this problem is to apply more pressure at the center of the wafer than at the edge. However, it may be difficult to increase the contact pressure between the polishing pad and the wafer only at the center of the wafer because of the characteristics of the polishing pad, and thus the oxide film etch rate may increase across the wafer. Besides being difficult to apply more pressure to only the center of the wafer in an actual practice, there is a risk that the wafer will be scratched. In fact, the increased pressure may prevent the surface of the layer being polishing from being chemically polished, because the increased pressure may impede the delivery of slurry, which contains the reactant solution, to the contact area between the wafer and the polishing layers PL.

SUMMARY OF THE INVENTION

The present invention is therefore directed to a fixed abrasive polishing pad, a method of preparing the same, and chemical mechanical polishing apparatus including the same, which substantially overcome one or more of the problems due to the limitations and disadvantages of the related art.
It is therefore a feature of an embodiment of the present invention to provide a polishing pad including a base having polishing layers, the polishing layers having apertures.
It is therefore another feature of an embodiment of the present invention to provide a polishing pad having polishing layers with apertures formed therein, which may enhance the ability of a slurry to infiltrate a contact area between the polishing layers and a target substrate.
It is therefore yet another feature of an embodiment of the present invention to provide a polishing pad having polishing layers with apertures formed therein, where the area percentage of apertures in central polishing pad layers is different from the area percentage of apertures in edge polishing pad layers, such that a CMP rate may be adjusted across the surface of the polishing pad.
At least one of the above and other features and advantages of the present invention may be realized by providing a fixed abrasive polishing pad including a base and a plurality of polishing layers on the base, wherein each polishing layer includes abrasive particles and apertures in a polishing surface of the polishing layer.
At least some of the apertures may be interconnected within the polishing layer. The apertures may be formed using a foaming agent. The apertures may have a predetermined pattern in the polishing surface. The predetermined pattern may be a mold pattern. The apertures may be arranged at regular intervals. The apertures may have a regular shape. The apertures may occupy about 5-50% of the polishing surface of each of the polishing layers. The apertures may occupy about 5-30% of the polishing surface of each of the polishing layers.
The polishing pad may include central polishing layers disposed in a center region, and edge polishing layers disposed in an edge region, wherein the apertures in the central polishing layers may occupy a different area percentage of the polishing surface than do the apertures in the edge polishing layers. The aperture area percentage in the central polishing layers may be greater than the aperture area percentage in the edge polishing layers.
At least one of the above and other features and advantages of the present invention may also be realized by providing a method of manufacturing a fixed abrasive polishing pad, the method including forming a base and disposing polishing layers on the base, each of the polishing layers including apertures in a polishing surface thereof and abrasive particles.
The apertures may occupy about 5-50% of the polishing surface of each of the polishing layers. The apertures may occupy about 5-30% of the polishing surface of each of the polishing layers. The apertures may be formed by combining a foaming agent with a polymeric binder. Forming the polishing layers may include forming a mixture including the polymeric binder and the foaming agent, forming apertures in the mixture using the foaming agent, distributing abrasive particles in the mixture, and forming the polishing layers by processing the mixture including the distributed abrasive particles using a printing process. The apertures may be formed by heating the foaming agent. The foaming agent may include at least one of Na₂SO₄, NaHCO₃, ADCA, OBSH, and TSH.
The apertures may be formed using a mold having a predetermined pattern therein, the pattern corresponding to a pattern of apertures in the polishing surface. Forming the apertures may include distributing abrasive particles in a UV-hardenable polymeric binder, molding the polishing layers using the mold, and irradiating the molded polishing layers with UV light. Forming the apertures may include distributing abrasive particles in a thermosetting polymeric binder, molding the polishing layers using the mold, and heating the molded polishing layers. The mold may include a fine pattern of projections on a molding surface, the projections forming the apertures in the polishing surface.
At least one of the above and other features and advantages of the present invention may further be realized by providing a chemical mechanical polishing apparatus, including a wafer carrier, a fixed abrasive polishing pad including a base and polishing layers disposed on the base, a slurry supplier, and a supporter supporting the polishing pad, wherein each polishing layer includes abrasive particles, and apertures formed in a polishing surface of the polishing layer.
The polishing layers may be formed using a foaming agent. The apertures may have a predetermined pattern in the polishing surface. The chemical mechanical polishing apparatus may be rotary type having a first roller for supplying the polishing pad, and a second roller for receiving a portion of the polishing pad that has performed a polishing process.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which:
FIG. 1 photographically illustrates an upper surface of a conventional fixed abrasive polishing pad;
FIGS. 2A and 2B are magnified portions of a polishing layer of the polishing pad of FIG. 1;
FIG. 3 illustrates a graph of results of a polishing operation performed using a chemical mechanical polishing (CMP) apparatus including the conventional fixed abrasive polishing pad of FIG. 1;
FIG. 4 illustrates a perspective view of a fixed abrasive polishing pad according to an embodiment of the present invention;
FIG. 5 illustrates a cross-section of a polishing layer of the polishing pad of FIG. 4;
FIG. 6 illustrates a perspective view of a fixed abrasive polishing pad according to another embodiment of the present invention;
FIG. 7 illustrates a cross-section of a polishing layer of the polishing pad of FIG. 6; and
FIG. 8 illustrates a schematic view of a CMP apparatus including a fixed abrasive polishing pad according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Korean Patent Application Nos. 10-2005-0119089 and 10-2006-0047120, filed on Dec. 7, 2005, and May 25, 2006, respectively, in the Korean Intellectual Property Office, both of which are entitled “Fixed Abrasive Polishing Pad, Method of Preparing the Same, and Chemical Mechanical Polishing Apparatus Including the Same,” are incorporated by reference herein in their entirety.
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are illustrated. The invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
In the figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout.
Embodiments of the present invention are directed to a fixed abrasive polishing pad which may include apertures and abrasive particles, and which may minimize damage to a target wafer while evenly polishing the entire surface of the wafer during CMP, and a method of making the same. An embodiment of the present invention is also directed to a CMP apparatus which may evenly polish the entire surface of the target wafer, which may enhance productivity and which may improve reliability of a semiconductor device made therewith.
The apertures or recesses in the polishing pad may allow a slurry to exist in contact areas between the wafer and each of the polishing layers, so that both mechanical polishing by abrasive particles and chemical polishing by a reactive agent in the slurry may be effected. In particular, spaces may be formed in the contact areas due to the apertures, which may allow slurry to be contained in the spaces. Thus, a chemical reaction between the slurry and the wafer may be effected. In addition, since abrasive particles included in the polishing layers may be easily carried out by the slurry, mechanical polishing may also be effected. Therefore, the use of a polishing pad according to the present invention may allow the entire surface of the wafer to be evenly chemically-mechanically polished. The CMP apparatus may include a rotary-type polishing pad, so that continuous CMP processes may be conducted without need to frequently replace the polishing pad as the polishing layers are consumed.
FIG. 4 illustrates a perspective view of a fixed abrasive polishing pad according to an embodiment of the present invention, and FIG. 5 illustrates a cross-section of a polishing layer of the polishing pad of FIG. 4. Referring to FIGS. 4 and 5, a fixed abrasive polishing pad 30 may include a plurality of polishing layers 31 arranged on a base 32, the polishing layers 31 including abrasive particles 36 and apertures 38.
The base 32 may include a polymer exhibiting suitable strength, elasticity and durability. When the fixed abrasive polishing pad 30 is a rotary type pad, the base 32 should have enough elasticity to maintain sufficient tension to prevent the base 32 from loosening.
The base 32 may be a single layer. Alternatively, since it may be desirable for the base 32 to exhibit characteristics such as strength, elasticity, and durability, the base 32 may be a multi-layer structure obtained by stacking materials exhibiting the aforementioned characteristics. For example, a rotary-type polishing pad may have a base 32 made up of a flexible underlayer and a hard upper layer that is disposed on the flexible underlayer, so that the performance of the polishing pad increases while the polishing pad is also flexible enough to be bent around rollers.
The base 32 may be formed of, e.g., polyurethane, polyester, polyether, epoxy, polyimide, polycarbonate, polyethylene, polypropylene, latex, nitrile rubber, isoprene rubber, or any other suitable material. Polyurethane may be a particularly suitable material for the base 32.
The polishing layers 31 may be formed on the base 32 after forming the base 32. The polishing layers 31 may include the abrasive particles 36 distributed in a polymer 34. As the polymer 34 may be gradually reduced during the CMP process by the action of the slurry, the abrasive particles 36 contained in the polymer 34 may be exposed and rub against the target wafer.
The polymer 34 may allow the abrasive particles 36 therein to be gradually exposed by the polishing action of the slurry, so as to abrade the target wafer. The polymer 34 may be formed using polymeric binders, e.g., thermoplastic materials, thermosetting materials, ultraviolet (UV) hardenable materials, etc. The polymer 34 may be, e.g., polyurethane, polypropylene, polyacryl, polyethylene, a block co-polymer, etc. The polymer 34 may be formed of, e.g., a mixture of an active hydrogen compound used to form polyurethane and an isocyanate as a polymerization catalyst. The polymer 34 may be sintered or hardened by heat or UV light and fixed onto the base 32.
The abrasive particles 36 may be distributed in the polymer 34 to thereby form the polishing layers 31. The abrasive particles 36 may be, e.g., silica (SiO₂), ceria (CeO₂), alumina (Al₂O₃), etc. In a CMP process for an STI oxide film, ceria may be particularly suitable for the abrasive particles 36.
The polishing layers 31 may have various shapes and sizes, which may be determined according to, e.g., the target wafer to be polished, the bonding agents, the nature of the abrasive particles, the polishing process conditions, etc. Where the pad 30 is used in a CMP process for an STI oxide film, each of the polishing layers 31 may have a width of about 50-200 μm and a thickness of about 20-50 μm.
The polishing layers 31 may include various additives suitable for enhancing the CMP process. The additives may include, e.g., one or more of a viscosity modifier, a wetting agent, etc. The viscosity modifier may be employed to enhance the lubrication property of the polishing layers 31 when the polishing layers 31 contact the wafer, so that the abrasive particles or the additives spread evenly over areas of the wafer that contact the polishing layers 31. Hence, the viscosity modifier may enhance the CMP planarization. The viscosity modifier may include, e.g., ethylene glycol or a nonionic polymer compound, such as a gum compound. The wetting agent may be employed to improve the miscibility and dispersiveness of the abrasive particles 36 across the polymer 34.
Referring to FIG. 5, slurry may reside in the apertures 38 during CMP. Hence, a chemical reaction between the slurry and the wafer may occur in the contact between the polishing layers 31 and the wafer, even in consideration of a predetermined pressure that may be applied to the pad 30 in order to accelerate polishing. The slurry may include various materials suitable for the object to be polished. For example, for CMP of a wafer 20 having an STI oxide film formed thereon, the slurry may include, e.g., one or more of an oxidizing agent, an etch solution, and a surface active agent.
The apertures 38 may be formed in the polymer 34. The apertures 38 may have various shapes, and may be formed by various methods. The apertures 38 may or may not be interconnected within each polishing layer 31. The area of the apertures 38 may occupy about 5-50% of the area of each of the polishing layers 31. In an implementation, the area of the apertures 38 may occupy about 5-30% of the area of each of the polishing layers 31. If a small number of apertures 38 are formed in each polishing layer 31, the amount of slurry contained in the apertures 38 may be low, and the chemical polishing process may not be efficient. If a large number of apertures 38 are formed in each polishing layer 31, the amount of abrasive particles 39 contained in the polymer 34 of each polishing layer 31 may be reduced, and the mechanical polishing process may not be efficient.
In an implementation, the percentage of each polishing layer 31 occupied by the apertures 38 may be substantially uniform. In another implementation, the percentages of the polishing layers 31 occupied by the apertures 38 may be different across the pad 30, in order to control polishing rates on different areas on the wafer. For example, if the polishing and removal rate tends to be lower at the center of the target wafer than that of the edge, a greater number of apertures 38 may be formed in those polishing layers 31 that are located at the center of the pad 30, relative to the number of apertures formed in those polishing layers 31 that are located on the edge of the pad 30.
The apertures 38 may be formed by combining a foaming agent with a polymeric binder during formation of the polishing layers 31. The foaming agent may be an inorganic foaming agent such as Na₂SO₄, NaHCO₃, etc., or an organic foaming agent such as azocarbonamide (ADCA), OBSH (p,p′-oxybis(benzenesulfonylhydrazide)), TSH (p-tolunesulfonylhydrazide), etc. The amount of the foaming agent used may vary according to the size, polishing speed, or other desired characteristics of the polishing layers 31.
The apertures 38 may be, e.g., pores, and may be formed by injecting the foaming agent into a polymeric binder so as to form a mixture, and then apertures may be formed in the mixture by using a foaming machine or by heating the mixture. Thereafter, the mixture may be poured into a previously manufactured mold and hardened, e.g., using UV light or heat, to thereby form the polishing layers 31. The polishing layers 31 may be attached to the base 32 to make the polishing pad 30.
Different amounts of foaming agent may be used in those polishing layers 31 that correspond to the center of the wafer as compared to those corresponding to the edge of the wafer. That is, if the polishing rate at the center of the wafer is less than that at the edge thereof, the polishing rate at the center of the wafer may be increased by using a greater amount of the foaming agent in the polishing layers 31 that are disposed in the center of the polishing pad 30 than in those corresponding to the edge of the wafer.
FIG. 6 illustrates a perspective view of a fixed abrasive polishing pad according to another embodiment of the present invention, and FIG. 7 illustrates a cross-section of a polishing layer of the polishing pad of FIG. 6. Referring to FIG. 6, a fixed abrasive polishing pad 30′ may include the base 32 and polishing layers 33. The polishing layers 33 may include the abrasive particles 36 and the polymer 34, as described above in connection with FIG. 4. Referring to FIGS. 6 and 7, the polishing layers 33 may include apertures 39 that have predetermined forms and a regular arrangement or pattern.
The apertures 39 may be formed using, e.g., a mold having a fine concave/convex structure. The abrasive particles 36 may be distributed in a polymeric binder so as to form a mixture, which may then be poured into a mold corresponding to each the polishing layers 33 having the apertures 39. UV light, heat, etc., may be applied to the mixture in order to harden the polymer 34, to thereby form the polishing layers 33. The polishing layers 33 may be attached to the base 32 to form the pad 30′ of FIG. 6.
Apertures 39, in the form of, e.g., recesses or grooves, may be formed in the polishing layers 33. The apertures 39 may be formed using a mold having a fine structure of an inverse pattern, e.g., a concave/convex structure. The mold may include a fine pattern of projections on a molding surface, so that, during molding, the projections form the apertures 39 in the polishing surface of the polishing layers 33. The mold used for those polishing layers 33 that correspond to the center of the wafer may be different from the mold used for those polishing layers 33 that correspond to the edge of the wafer. If the polishing rate at the center of the wafer is less than that at the edge thereof, the polishing rate at the center of the wafer may be increased by using mold that forms a predetermined pattern having a greater amount of aperture area for the polishing layers 33 that are disposed in the center of the polishing pad 30, and using a mold that forms a different predetermined pattern having a lesser amount of aperture area for the polishing layers 33 that correspond to the edge of the wafer.
The shape of the apertures 39 may be suitably varied by varying to the shapes of the concave and/or convex structures in the mold. The apertures 39 may be, e.g., tetrahedral, hexahedral, etc. The depth of the apertures 39 may be less than the thickness of the polishing layer 33, such that the apertures 39 do not completely penetrate through the polishing layer 33. The area of the apertures 39 may occupy about 5-50% of the area of each of the polishing layers 33. In an implementation, the area of the apertures 39 may occupy about 5-30% of the area of each of the polishing layers 33.
For a UV-hardenable polymer 34, the polymer 34, into which abrasive particles 36 may be evenly dispersed, may be partially or completely hardened by UV light projected onto the polymer 34, and then molded using the mold, thereby forming the apertures 39 corresponding to the fine concave/convex structure of the mold. Similarly, apertures 39 may be formed in a thermosetting polymer 34 by molding the polymer 34 using the mold after heating the polymer 34.
Referring to FIG. 7, the abrasive particles 36 and the apertures 39 may be evenly distributed in the polymer 34. By using a mold having regular features, the apertures 39 may be arranged at regular intervals. In an implementation, the apertures 39 formed in each of the polishing. layers 33 may have the same shapes and area percentages, in order to equalize the amount of slurry contained in each the polishing layers 33 across all of the polishing layers 33. This may enhance the uniformity of the chemical reactions occurring during wafer polishing. Alternatively, as described above, the polishing pad may be formed with differing aperture area ratios for, e.g., the center and edge polishing layers 33. In particular, the approaches described above in connection with FIGS. 4 and 6 may be employed.
The fixed abrasive polishing pads 30, 30′ described above may be, e.g., flat, circular type or a rotary type pads. FIG. 8 illustrates a schematic view of a CMP apparatus including a fixed abrasive polishing pad according to an embodiment of the present invention. The CMP apparatus of FIG. 8 is a rotary-type CMP apparatus, and the polishing pad illustrated in FIG. 8 may be, e.g., the polishing pad 30 of FIG. 4. Of course, the polishing pad employed may be, e.g., the pad 30′ having the polishing layers 33 formed thereon (not shown). Referring to FIG. 8, the CMP apparatus may include the polishing pad 30, wherein the polishing layers 31, including abrasive particles 36 and apertures 38, are formed on the base 32.
The polishing layers 31 may be formed to have a width of about 50-200 μm and a thickness of about 20-50 μm. Note that, in FIG. 8, the polishing layers 31 are illustrated with exaggerated dimensions for clarity.
The polishing pad 30 may be initially wound around a first roller 50. The polishing pad 30 may be unwound from the first roller 50 and travel on a supporter 40, e.g., a platen. A wafer 20 may be carried by a wafer carrier 10 to be located over the polishing pad 30. When the wafer carrier 20 descends, a layer of the target wafer 20 may be chemically-mechanically polished by rubbing against the polishing layers 31 of the polishing pad 30.
The CMP apparatus may further include a second roller 52 for winding up the polishing pad 30 as it is consumed. After use, the polishing pad 30 may be discarded. A slurry provider 60 may be employed to provide a slurry over the polishing pad 30.
The polymer 34 of the polishing layers 31 may be worn away by the slurry, allowing the abrasive particles 36 to rub against and abrade the to-be-polished layer of the wafer 20, whereby the wafer 20 is mechanically polished. The apertures 38 formed in the polishing layers 31 may contain the slurry, and the contained slurry and the to-be-polished layer of the wafer 20 may react with each other, whereby the wafer 20 is chemically polished. The chemical and mechanical action of the CMP process may continuously expose additional abrasive particles 36 in the polymer 34 that forms the polishing layers 31. Since the slurry can permeate into the contact between the polishing pad 30 and the wafer 20 due to presence of the apertures 38, chemical polishing may be enhanced. Furthermore, since the abrasive particles 36 at the center of the contact may be exposed and released by flow of the slurry contained in the apertures 38 from the central portion of the contact, mechanical polishing may be even across the surface of the to-be-polished layer of the wafer 20.
As described above, in a fixed abrasive polishing pad according to the present invention, polishing layers having apertures and disposed on a base, so that a slurry can be contained in the apertures near the contact between the polishing layers and a to-be-polished layer of a wafer. The slurry contained in the apertures may thus react with the to-be-polished layer, so that chemical polishing is effected. Simultaneously, abrasive particles in the polishing layers exposed and released by the slurry may abrade the wafer 20, so that mechanical polishing is effected. By utilizing the fixed abrasive polishing pad according to the present invention in a CMP process, the to-be-polished layer may be evenly polished, and the reliability and productivity of a semiconductor device manufactured thereby may be improved.
Exemplary embodiments of the present invention have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.

Claims

1. A fixed abrasive polishing pad, comprising:

a base; and

a plurality of polishing layers on the base, wherein each polishing layer includes:

abrasive particles, and

apertures in a polishing surface of the polishing layer.

2. The fixed abrasive polishing pad as claimed in claim 1, wherein at least some of the apertures are interconnected within the polishing layer.

3. The fixed abrasive polishing pad as claimed in claim 1, wherein the apertures are formed using a foaming agent.

4. The fixed abrasive polishing pad as claimed in claim 1, wherein the apertures have a predetermined pattern in the polishing surface.

5. The fixed abrasive polishing pad as claimed in claim 4, wherein the predetermined pattern is a mold pattern.

6. The fixed abrasive polishing pad as claimed in claim 4, wherein the apertures are arranged at regular intervals.

7. The fixed abrasive polishing pad as claimed in claim 4, wherein the apertures have a regular shape.

8. The fixed abrasive polishing pad as claimed in claim 1, wherein the apertures occupy about 5-50% of the polishing surface of each of the polishing layers.

9. The fixed abrasive polishing pad as claimed in claim 8, wherein the apertures occupy about 5-30% of the polishing surface of each of the polishing layers.

10. The fixed abrasive polishing pad as claimed in claim 1, wherein the polishing pad includes:

central polishing layers disposed in a center region; and

edge polishing layers disposed in an edge region, wherein the apertures in the polishing surface of the central polishing layers occupy a different area percentage of the polishing surface than do the apertures in the polishing surface of the edge polishing layers.

11. The fixed abrasive polishing pad as claimed in claim 10, wherein the aperture area percentage in the central polishing layers is greater than the aperture area percentage in the edge polishing layers.

12. A method of manufacturing a fixed abrasive polishing pad, the method comprising:

forming a base; and

disposing polishing layers on the base, each of the polishing layers including apertures in a polishing surface thereof and abrasive particles.

13. The method as claimed in claim 12, wherein the apertures occupy about 5-50% of the polishing surface of each of the polishing layers.

14. The method as claimed in claim 13, wherein the apertures occupy about 5-30% of the polishing surface of each of the polishing layers.

15. The method as claimed in claim 12, wherein the apertures are formed by combining a foaming agent with a polymeric binder.

16. The method as claimed in claim 15, wherein forming the polishing layers comprises:

forming a mixture including the polymeric binder and the foaming agent;

forming apertures in the mixture using the foaming agent;

distributing abrasive particles in the mixture; and

forming the polishing layers by processing the mixture including the distributed abrasive particles using a printing process.

17. The method as claimed in claim 16, wherein the apertures are formed by heating the foaming agent.

18. The method as claimed in claim 15, wherein the foaming agent includes at least one of Na₂SO₄, NaHCO₃, ADCA, OBSH, and TSH.

19. The method as claimed in claim 12, wherein the apertures are formed using a mold having a predetermined pattern therein, the pattern corresponding to a pattern of apertures in the polishing surface.

20. The method as claimed in claim 19, wherein forming the apertures includes:

distributing abrasive particles in a UV-hardenable polymeric binder;

molding the polishing layers using the mold; and

irradiating the molded polishing layers with UV light.

21. The method as claimed in claim 19, wherein forming the apertures includes:

distributing abrasive particles in a thermosetting polymeric binder;

molding the polishing layers using the mold; and

heating the molded polishing layers.

22. The method as claimed in claim 19, wherein the mold includes a fine pattern of projections on a molding surface, the projections forming the apertures in the polishing surface.

23. A chemical mechanical polishing apparatus, comprising:

a wafer carrier;

a fixed abrasive polishing pad including a base and polishing layers disposed on the base;

a slurry supplier; and

a supporter supporting the polishing pad, wherein each polishing layer includes:

abrasive particles, and

apertures formed in a polishing surface of the polishing layer.

24. The chemical mechanical polishing apparatus as claimed in claim 23, wherein the polishing layers are formed using a foaming agent.

25. The chemical mechanical polishing apparatus as claimed in claim 23, wherein the apertures have a predetermined pattern in the polishing surface.

26. The chemical mechanical polishing apparatus as claimed in claim 23, wherein the chemical mechanical polishing apparatus is rotary type having a first roller for supplying the polishing pad, and a second roller for receiving a portion of the polishing pad that has performed a polishing process.