JP2018058203A - Apparatus for shaping the surface of chemical mechanical polishing pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for making pre-conditioned CMP pads that have a consistent pad surface microtexture while retaining their original surface topography.SOLUTION: The apparatus comprises: a rotary grinder assembly 4 having a rotor with a grinding surface of a porous abrasive material 2; a flat bed platen 1 for holding a CMP polishing layer 2 in place so that the grinding surface of the rotary grinder is disposed above and parallel to the surface of the flat bed platen to form an interface between a surface of the CMP polishing layer and the porous abrasive material; and a substrate holder 6 disposed above and parallel to a top surface of the flat bed platen so as not to overlap a region on which the rotary grinder assembly is mounted and to which a CMP substrate 7 is attached; thereby creating a polishing interface between the surface of the substrate and the CMP polishing layer to allow the substrate holder to rotate independently from the rotary grinder assembly and the flat bed platen.SELECTED DRAWING: Figure 3

Description

  The present invention is for use in providing pad surface microtextures on polishing pads, such as polymer pads, used for chemical mechanical planarization (CMP) of substrates, such as semiconductor substrates, magnetic substrates, and optical substrates. And a method for using the device. In particular, the present invention is an apparatus for grinding the surface of a CMP polishing layer, wherein the polishing surface of the porous abrasive material is formed so as to form an interface between the surface of the CMP polishing layer and the porous abrasive material. The apparatus includes a rotating grinder having a flat bed platen for holding a CMP polishing layer in place.

  Fabrication of a polishing pad for use in chemical mechanical planarization involves molding and curing a foamed or porous polymer (eg, polyurethane) in a mold having the desired diameter of the final polishing pad, then Cutting the cured polymer from the mold and cutting it in a direction parallel to the upper surface of the mold to form a layer having the desired thickness, for example by peeling it apart, and then molding the resulting layer It is known to include, for example, grinding, routing, or embossing the final surface design on top of the polishing pad. Conventionally, known methods for forming such a layer into a polishing pad include injection molding the layer, extruding the layer, buffing the layer with a fixed abrasive belt, and / or layer. Finishing the surface to the desired thickness and flatness. These methods have limited ability to achieve consistent pad surface microtextures that require low defectivity of the polished substrate and to achieve uniform removal of material from the substrate. In fact, these methods generally produce a visible design (eg, a groove of a given width and depth) and a visible but inconsistent texture. For example, the method of peeling thinly has low reliability regarding the formation of the pad surface. This is because the rigidity of the mold varies with the thickness of the mold, and the blade of the stripper is continuously worn away. One point facing the technology was that consistent micro-texture of the pad surface could not be obtained throughout due to continuous tool wear and lathe positioning accuracy. Pads made by the injection molding process lack uniformity due to inconsistent material flow throughout the mold. Furthermore, the molded product tends to deform when the pad is fixed and cured. This is because the hardened and remaining parts of the molding material can flow at different rates during injection, particularly at high temperatures, into a limited area.

  The buffing method has also been used to smooth chemical mechanical polishing pads having a harder surface. In one example of a buffing method, US Pat. No. 7,118,461 by West et al. Discloses a smooth pad for chemical mechanical planarization and a method for making a pad, the method comprising: It includes buffing or polishing the surface of the pad with an abrasive belt to remove material from the surface. Buffing, in one example, was to follow a subsequent buffing process with smaller abrasive grains. Products by this method exhibit improved planarization capability over the same pad product that has not been smoothed. Unfortunately, although West's method can smooth the pads, they do not provide a consistent texture of the pad surface throughout and softer pads (pad or pad polymer matrix ASTM D2240-15 ( 2015) Shore D hardness of 40 or less). Furthermore, West et al. Removes so much material that the useful life of the resulting polishing pad can be adversely affected. It remains desirable to provide a chemical mechanical polishing pad that has a consistent surface microtexture without limiting the useful life of the pad.

  Adjustment of a chemical mechanical polishing pad is similar to buffing, and the pad is generally tuned for use with a rotating polishing wheel having a surface resembling fine sandpaper. Such adjustment provides an improved planarization effect after a “break-in” period during which the pad is not used for polishing. It remains desirable to eliminate the run-in period and to provide a preconditioned pad that can be used immediately for polishing.

  The inventors have sought to find an apparatus for making a preconditioned CMP pad that has a consistently uniform pad surface microtexture while maintaining the original surface morphology.

  1. In accordance with the present invention, to provide a chemical mechanical (CMP) polishing pad or layer of a preconditioned polymer, preferably a porous polymer, polyurethane, or polyurethane foam, having a fine pad surface texture that is effective for polishing. A rotating grinder assembly having a wheel or rotor having a grinding surface of porous abrasive material, and a flat bed platen for holding the CMP polishing layer in place, for example by pressure sensitive adhesive or preferably vacuum The grinding surface of the rotating grinder is disposed above and parallel or substantially parallel to the surface of the flat bed platen so as to form an interface between the surface of the CMP polishing layer and the porous abrasive material. .

  2. According to the apparatus of the invention as described in item 1 above, the CMP polishing layer has a radius extending from its center point to its outer periphery and grinding of the wheel or rotor of the rotating grinder assembly The surface has a diameter equal to or longer than the radius of the CMP polishing layer, preferably equal to the radius of the CMP polishing layer.

  3. According to the apparatus of the present invention as described in item 2 above, the wheel or rotor of the rotating grinder assembly is such that the outer periphery of its grinding surface is supported directly on the center of the CMP polishing layer during grinding. Be placed

  4). According to the apparatus of the present invention as described in any one of items 1, 2, or 3 above, each of the wheel or rotor of the rotating grinder assembly, the CMP polishing layer, and the flat bed platen is made of a CMP polishing layer. Rotates during grinding. Preferably, the flat bed platen rotates in the opposite direction to the rotating grinder assembly.

  5. According to the device of the invention as described in item 4 above, the wheel or rotor of the rotating grinder assembly rotates at a speed (number of revolutions) of 50 to 500 revolutions per minute, preferably 150 to 300 revolutions per minute. The flat bed platen rotates at a speed of 6 to 45 revolutions per minute, preferably 8 to 20 revolutions per minute.

  6). According to the apparatus of the present invention as described in any one of items 1, 2, 3, 4 or 5 above, the wheel or rotor of the rotating grinder assembly is capable of polishing the CMP polishing layer and the flat bed platen during grinding. The rotating grinder is placed on top and sent downward from a point directly above the surface of the CMP polishing layer at a rate of 0.1-15 μm / rotation, or preferably 0.2-10 μm / rotation, ie CMP. The interface between the surface of the polishing layer and the porous abrasive is reduced.

  7). According to the apparatus of the present invention as described in any one of items 1, 2, 3, 4, 5, or 6 above, the rotary grinder assembly is a motor or rotary actuator (eg an electric motor or servomotor). ) And a vertically arranged shaft connected to and driven (eg, via a gear or drive belt) with a motor or rotary actuator, extending into the drive housing and having a wheel or rotor A shaft is connected at its lower end to a wheel or rotor via a mechanical coupling (e.g. gear or drive belt) so that it rotates at a desired speed (rpm) per minute.

  8). According to the device of the invention as described in item 7 above, the vertically arranged shaft in the drive housing is either a ball screw or a second screw arranged where the shaft is connected to a motor or rotary actuator. Servo motors are provided, and the wheel or rotor of the rotating grinder assembly can be sent downward at a predetermined incremental speed, either at the mechanical connection of the shaft to the wheel or rotor, or at both positions.

  9. According to the device of the invention as described in item 8 above, the wheel or rotor is one or more eccentric pneumatic actuators, such as cylinders, electronic actuators or motor actuators (for example servomotors), preferably wheels or rotors. 3 to 8 of such actuators arranged in a radial array around the rotor so that the wheel or rotor is such that its grinding surface is substantially parallel to the upper surface of the flat bed platen It can be tilted to allow grinding to produce a center thick or thin thin CMP polishing layer or pad.

  10. According to the apparatus of the present invention, the rotating grinder assembly has a wheel or rotor with a porous abrasive grinding medium (preferably supported on a single transport ring), the grinding medium being, for example, porous Perimeter of the transport ring via a radial array of clips, fasteners, or lateral spring-loaded snap rings located on the underside of the rotating grinder assembly where the periphery of the abrasive ring fits snugly It is attached to the underside of the section.

  11. According to the apparatus of the present invention as described in item 11 above, the porous abrasive grinding media is disposed in a plurality of segments, the plurality of segments around the lower side of the periphery of the rotating grinder assembly. And a gap is formed between the plurality of segments.

  12 According to the apparatus of the present invention as described in any one of items 1-11 above, the porous abrasive material is finely divided non-porous abrasive particles, such as boron nitride, or preferably It is a mixture of porous continuous phases having diamond particles dispersed therein.

  13. According to the apparatus of the present invention as described in item 12 above, the porous continuous phase of the porous abrasive has an average pore diameter of 3 to 240 μm, or preferably 10 to 80 μm.

  14 According to the apparatus of the invention as described in any one of items 8 or 9 above, the porous continuous phase of the porous abrasive material is a ceramic, preferably a sintered ceramic (eg alumina or ceria). ) Is included.

  15. According to the apparatus of the present invention as described in any one of items 1-14 above, the flat bed platen has a plurality of small holes (e.g. 0.5 to 0.5 mm in diameter) throughout the platen connected to the vacuum apparatus. 5mm). The plurality of holes are adapted to hold the substrate of the CMP polishing layer in place during grinding, for example, along a series of spokes extending outward from the center point of the flat bed platen or in a series of concentric rings. May be arranged in any suitable manner.

  16. According to the device of the invention as described in any one of items 1 to 15 above, a conduit, hose, for blowing intermittently or preferably continuously a compressed inert gas or air , A nozzle or valve, and during grinding, preferably from a point proximate to the center point of the CMP polishing layer on the flat bed platen to the porous abrasive through the interface between the CMP polishing layer and the porous abrasive Operatively arranged to blow the compressed inert gas or air onto the interface between the surface of the CMP abrasive layer material and the porous abrasive material, or more preferably, a conduit, hose, nozzle, Alternatively, the valve may be inert gas or air so as to act on the porous abrasive material through the interface between the CMP abrasive layer and the porous abrasive material from a point close to the center point of the CMP abrasive layer on the flat bed platen. I will blow And a second conduit for separately blowing the compressed inert gas or air upward from a point directly below the periphery of the rotating grinder assembly to act on the porous abrasive during grinding. For example, a peripheral portion of the CMP polishing layer and a peripheral portion of the rotating grinder cooperate with each other.

  17. According to an apparatus of the present invention as described in any one of items 1 to 16 above, the apparatus is provided with a rotating grinder assembly and a CMP substrate (eg a semiconductor substrate or wafer, a magnetic substrate or an optical substrate). A substrate holder disposed above and in parallel with the upper surface of the flat-bed platen so that it does not overlap with the area where the substrate is attached (eg clamped), whereby the surface of the substrate and the CMP polishing layer The substrate holder rotates independently of the rotating grinder assembly and the flat bed platen at a unique speed of, for example, 1 to 200 revolutions per minute, preferably 10 to 100 revolutions per minute. To do.

  18. According to the apparatus of the present invention as described in item 17 above, the substrate holder has a diameter smaller than the radius of the CMP polishing layer or pad held on the flat bed platen, and further, the substrate holder comprises: A second actuator for mechanically coupling to or mounted on a first actuator (eg, servomotor) for rotating the grinder about the central axis and for pressing the substrate holder against the CMP polishing layer or pad (For example, a second servo motor or a Z-axis ball screw) is mechanically connected or mounted.

  19. According to the device of the invention as described in any one of items 1 to 18 above, the entire device has an airtight housing, for example a relative humidity (RH) of 5 to 100%, for example 5 to 50%. It is enclosed inside what can be reached.

  Unless otherwise indicated, temperature and pressure conditions are air temperature and standard pressure. All ranges described are inclusive and combinable.

  Unless otherwise indicated, any term that includes parentheses refers to the entire term without parentheses, the term excluding the words in parentheses, and the combination of the former two. Thus, for example, the term “(poly) isocyanate” refers to isocyanate, polyisocyanate, or mixtures thereof.

  All ranges are inclusive and combinable. For example, the term “50 to 3000 cPs, or 100 cPs or more” includes each of 50 to 100 cPs, 50 to 3000 cPs, and 100 to 3000 cPs.

  As used herein, the term “ASTM” refers to a publication of ASTM International (West Conshohocken, Pennsylvania).

  As used herein, the term “thickness variation” means a value determined by the maximum variation in the thickness of the CMP polishing pad.

  As used herein, the term “substantially parallel” refers to the angle formed by the grinding surface of the rotating grinder and the top surface of the CMP polishing layer, more particularly 178 ° to 182 °, or preferably Refers to an angle between 179 ° and 181 °, which is parallel to the grinding surface of the rotating grinder and ends at a point above the center point of the CMP polishing layer, from the end of the first line segment element and Defined by the intersection with a second line segment element that runs parallel to the upper surface of the flat bed platen and ends at the outer periphery of the flat bed platen. Here, the first and second line segment elements are perpendicular to the flat bed platen and on the periphery of the grinding surface of the rotating grinder disposed farthest from the center point of the CMP polishing layer and the center point of the CMP polishing layer. It exists in a plane that runs through points.

  As used herein, the term “Sq” when used to define surface roughness is a specified number measured at a specified point on the surface of a given CMP polishing layer. Means the root mean square of the surface roughness value.

  As used herein, the term “surface roughness” is the best-fit plane that represents a horizontal plane that is parallel to the top surface of a given CMP polishing layer and located on any given top surface. Means the value determined by measuring the height of the surface relative to. Acceptable surface roughness ranges from 0.01 μm to 25 μm (Sq) or preferably from 1 μm to 15 μm (Sq).

  As used herein, the term “wt%” represents weight percent.

1 is a schematic perspective view of a rotating grinder apparatus according to the present invention showing a CMP polishing layer including a flat bed platen and a transparent window. FIG. FIG. 2 is a top view of a CMP polishing layer treated with the apparatus of the present invention, having a consistent microtexture on its surface throughout the groove defined by intersecting arcs, each arc being It has a radius of curvature equal to or slightly larger than the radius of the CMP polishing layer. 1 is a schematic perspective view of a rotating grinder and polishing apparatus according to the present invention having a substrate holder for planarizing or polishing a substrate, eg, a semiconductor.

  According to the present invention, the grinding device improves the microtexture of the surface of the CMP polishing layer (including the CMP polishing pad and the upper surface of the polishing layer). The apparatus consists of a series of intersecting arcs in the CMP polishing layer (having the same radius of curvature as the circle defined by the outer edge of the grinding surface of the rotating grinder) and 0.01-25 μm on the upper surface of the CMP polishing layer. Create a consistent surface micro-texture characterized by surface roughness. The inventors have discovered that the CMP polishing layer processed by the rotating grinder according to the present invention performs well, i.e., is preconditioned, with little or no adjustment. Furthermore, the micro-texture on the pad surface of the rotating grindered CMP polishing layer results in improved polishing of the substrate. The apparatus of the present invention is a window material that is softer than the rest of the CMP polishing layer, and irregularities in the pad configuration due to surface defects, such as thin stripping that leads to a chemical mechanical polishing pad. Help to avoid foaming. In addition, the apparatus of the present invention results from the deformation of the polishing layer during the stacking of pads where two or more pad layers are passed through a nip that is spaced apart and set to produce a linear wave. Helps minimize negative collisions. This is essential for soft and compressible CMP polishing layers. In addition, the devices of the present invention and the processed pads they provide provide an optimized surface micro-texture, lower defects, and an improved cross-over across the substrate surface (eg, semiconductor or wafer surface). It is possible to remove various materials.

  The inventors have discovered that grinding of a CMP polishing layer using a porous abrasive allows grinding without adhesion of a grinding medium and without causing damage to the CMP polishing layer substrate. . The pores in the porous abrasive are large enough to store particles that are removed from the CMP polishing layer substrate. And the porosity of the porous abrasive is sufficient to store the bulk of the material removed during grinding. Preferably, blowing compressed air across the interface between the porous abrasive and the CMP polishing layer substrate further assists in the removal of the abrasive and prevents contamination of the grinding apparatus.

  In any method using the apparatus of the present invention, the blowing of compressed gas or air can also take place before or after grinding.

  The apparatus of the present invention may comprise a rotating grinder and a flat bed platen. The rotating grinder is lowered at a set or feed rate over a CMP polishing layer placed on a flat bed platen.

  As shown in FIG. 1, the apparatus of the present invention grinds the surface of a CMP polishing layer disposed on the surface of a flat bed platen (1) fitted with a vacuum port (not shown). The CMP polishing layer or pad (2) is disposed on the flat bed platen (1) such that the center point of the flat bed platen (1) and the CMP polishing layer (2) are aligned. The flat bed platen (1) in FIG. 1 has a vacuum vent (not shown) to hold the CMP polishing layer (2) in place. In FIG. 1, the CMP polishing layer (2) has one window (3). The grinding mechanism of the present invention comprises a rotating grinder (wheel) assembly (4) or a rotor to which a grinding medium including a porous abrasive (5) is attached on the lower side of a peripheral portion thereof, and a porous abrasive. (5) is arranged in a plurality of segments extending around the lower side of the periphery of the rotor (4) as shown. The plurality of se segments have small voids between them. In FIG. 1, the rotating grinder assembly (4) is positioned so that its periphery is directly above the center point of the CMP polishing layer (2) as desired. Further, the rotating grinder assembly (4) has a desired size such that its diameter is approximately equal to the diameter of the CMP polishing layer (2).

  The apparatus of the present invention may preferably include both a grinder / regulator and a polishing apparatus where a CMP polishing pad is mounted on a flat bed platen. Both the rotating grinder assembly and, independently, the substrate holder are then lowered onto the CMP polishing pad and onto the top of the CMP polishing layer to form an interface between them for each. The substrate holder includes a first actuator (for example, a servo motor for rotating the substrate holder around the central axis) and a second actuator (for example, a second servo motor for pressing the substrate holder against the CMP polishing pad or Z-axis ball screw) is mechanically connected or mounted.

  As shown in FIG. 3, the apparatus of the present invention polishes the substrate while grinding the surface of the CMP polishing layer disposed on the surface of the flat bed platen (1). The CMP polishing layer or pad (2) is disposed on the flat bed platen (1) such that the center point of the flat bed platen (1) and the CMP polishing layer (2) are aligned. The flat floor platen (1) in FIG. 3 has a vacuum exhaust port (not shown) so as to hold the CMP polishing layer (2) in place. In FIG. 3, the CMP polishing layer (2) has one window (3). The grinding mechanism of the present invention comprises a rotating grinder (wheel) assembly (4) or a rotor to which a grinding medium including a porous abrasive (5) is attached on the lower side of a peripheral portion thereof, and a porous abrasive. (5) is arranged in a plurality of segments extending around the lower side of the periphery of the rotor (4) as shown. Furthermore, the substrate holder (6) or wafer transporter offset from the rotating grinder assembly (4) holds the 300 mm wafer (7) underneath.

  The grinding and polishing apparatus operates as follows. A substrate (eg, a semiconductor wafer) is held on the lower surface of the substrate holder and pressed against the CMP polishing pad on the upper surface of the flat bed platen. The flat bed platen and the substrate holder are rotated relative to each other, thereby bringing the lower surface of the substrate into sliding contact with the polishing pad. At this time, an abrasive liquid nozzle (not shown) supplies an abrasive liquid (for example, aqueous silica, or a particle slurry of an abrasive oxide, carbide, or nitride) to the polishing pad. The lower surface of the substrate is polished by a combination of a mechanical polishing motion of abrasive particles in the abrasive liquid and a mechanical polishing motion of the surface of the CMP polishing layer.

  The rotating grinder of the present invention comprises a round rotating grinder assembly or rotor having a porous abrasive material attached to its periphery, and is preferably scored or discontinuous around the periphery of the rotating grinder With a portion or void. The lower side of the porous abrasive is the grinding surface of the rotating grinder. The porous abrasive can be in the form of a ring or ring segment that fits or attaches to the underside of the rotating grinder assembly. Porous abrasive is made of a radial array of downward segments (usually 10-40 segments of porous abrasive), or porous abrasive, with periodic perforations in it A perforated ring can be included. The voids or perforations are used to remove the abrasive and clean the porous abrasive prior to, during or after grinding with compressed gas or compressed air between the surface of the CMP polishing layer and the porous abrasive. It is possible to spray on the boundary surface. Furthermore, the cuts or voids in the porous abrasive aid in cooling the surface of the porous abrasive and the CMP polishing layer substrate during grinding.

  The apparatus of the present invention can be arranged to compensate for undesirable CMP substrate wear profiles, eg, that the CMP process results in inconsistent wear profiles (eg, too little or too much removal at the edge of the substrate). This can extend the pad life. In such an arrangement, the grinding surface of the rotating grinder assembly can be adjusted to be substantially parallel but not exactly parallel to the top surface of the flat bed platen or the CMP polishing layer. For example, the grinding surface of the rotating grinder has a central thickness (the rotational grinder perpendicular to the rotating grinder and the flat bed platen and located farthest from the center point of the CMP polishing layer and the center point of the CMP polishing layer). Adjust to provide an angle between the flat-bed platen radius in a plane that runs through a point at the periphery of the grinding surface that is greater than 180 °) or a thin center (an angle that is less than 180 °) Can be done.

  The apparatus of the present invention can be used in a humid environment, for example, with water or an abrasive aqueous slurry (eg, silica slurry or ceria slurry).

  The apparatus of the present invention can be scaled to fit various sizes of CMP polishing layers when the size of the rotating grinder element can be varied. According to the apparatus of the present invention, the flat bed platen must be larger than the CMP polishing layer or is preferably sized with a radius equal to or longer than the radius of the CMP polishing layer. The apparatus can thus be scaled to handle CMP polishing layers having a radius of 100 mm to 610 mm.

  Various rotating grinder assemblies can be used with multiple devices (one at a time) according to the present invention. The rotating grinder assembly is selected so that its diameter matches or is slightly larger than the diameter of the CMP polishing layer being ground. Alternatively, the rotating grinder assembly allows various diameters of porous abrasive grinding media rings or disks (preferably a single transport ring) to adhere to the underside of its periphery. It is adapted to.

  Various substrate holders can be used with multiple devices according to the present invention (one used at a time). The substrate holder is selected so that its diameter is smaller than the diameter of the CMP polishing layer used for polishing and larger than the diameter of the substrate to be polished.

  The apparatus of the present invention allows for the provision of a CMP polishing layer or pad that does not suffer from defects due to window expansion and thinning. Thus, according to the method using the apparatus of the present invention, the CMP polishing layer casts the polymer to form a porous molded article having the desired diameter or radius (which would be the size of the pad made thereby). Can be formed. The molded article is then stripped to the desired thickness (which would be the target thickness of a pad made according to the present invention) and then the desired pad surface microtexture on the pad polishing surface. Following the grinding of the pad or CMP polishing layer to provide.

  In the method using the apparatus of the present invention, grinding can be performed on a single layer or one pad and on a laminated pad having a subpad layer. Preferably, in the case of a laminated pad, the method includes grinding the CMP polishing layer after the pad has been laminated so that the grinding removes deformation in the laminated pad.

  A given CMP polishing pad can be formed by molding a polymer to form a CMP polishing layer for use as a pad and peeling off the molded polymer, or preferably the CMP polishing pad Forming a CMP polishing layer to form, and then molding the polymer and laminating the molded polymer so that the CMP polishing layer is laminated on top of a subpad or subbing layer having the same diameter as the CMP polishing layer Can be formed.

  In a method using the apparatus of the present invention, forming a CMP polishing pad, forming a groove in the pad (eg, by turning the pad), and having a radius of curvature greater than, preferably equal to, the radius of the polishing layer. Grinding the CMP polishing pad with a rotating grinder to form a pad surface microtexture comprising a series of visible intersecting arcs on the polishing surface, while simultaneously planarizing the substrate with the CMP polishing pad. Can be included. In such a method, the CMP polishing pad is conditioned during use and refinishes the surface.

  In a method using the apparatus of the present invention, forming a CMP polishing pad, forming a microtexture of the pad surface comprising a series of visible intersecting arcs on the polishing surface having a radius of curvature greater than, preferably equal to, the radius of the polishing layer. Grinding the CMP polishing pad with a rotating grinder to form, while simultaneously planarizing the substrate with the CMP polishing pad, and forming grooves in the pad (eg by turning the pad), Can be included.

  In addition, the apparatus of the present invention can be used as a CMP polishing or planarization tool, i.e., a grinding or polishing apparatus.

  In another aspect, the present invention provides a method of using the grinding or polishing apparatus of the present invention. In accordance with the method of using the grinding or polishing apparatus of the present invention, a CMP polishing pad is attached to the upper surface of a flat bed platen and the substrate (eg, a semiconductor wafer to be polished) is present on its lower surface on the flat bed platen. It is clamped to the substrate holder to be lowered onto the CMP polishing pad and continues to rotate all of the flat bed platen, rotating grinder assembly, and substrate holder.

  In the method using the grinding or polishing apparatus of the present invention, a polishing liquid comprising abrasive particles (eg, silica, ceria, or alumina, or a mixture thereof) is supplied onto and affixed thereon. It is done. During operation, the substrate holder applies a desired downward pressure to the flat bed platen of 2-69 kPa, preferably 3-48 kPa. The surface of the substrate held against the CMP polishing pad is flattened while the substrate holder and the flat bed platen are rotating.

  Preferably, in the method for polishing a substrate according to the present invention, the substrate holder and the flat bed platen are rotated in the same direction.

  The predetermined CMP polishing layer for use in accordance with the method using the apparatus of the present invention comprises a polymer or preferably a porous polymer, a Shore D hardness of 20-80 according to ASTM D2240-15 (2015), Or a polymer foam or filler comprising a porous polymer material, for example having 40 or less.

  Preferably, the method of the present invention can be performed on a CMP polishing pad including any pad made from a relatively soft polymer, and in the handling of soft pads having a Shore D hardness of 40 or less Find special use.

  Certain CMP polishing layers for use in accordance with the method using the apparatus of the present invention include one or more non-porous transparent window sections, such as non-porous polyurethane having a glass transition temperature (DSC) of 75-105 ° C. It further includes a window section, such as a window section that does not extend over the center point of the CMP polishing layer. In such a CMP polishing layer, the one or more window sections have a window thickness variation of less than 50 μm throughout the largest dimension of the window, for example, the larger of the round window diameter or the length or width of a rectangular window. It has a top surface defined by minutes.

Furthermore, a given CMP polishing layer for use in the method using the apparatus of the present invention may comprise a plurality of pores or microelements, preferably polymeric microspheres having an average particle size of 10-60 μm. Preferably, such a CMP polishing layer has an annular band that alternates between a high density and a low density extending outwardly from the center point of the CMP polishing layer to the outer periphery. For example, the higher density annular band has a higher density of 0.01-0.2 g / cm ³ than the lower density annular band.

  Thus, a chemical mechanical polishing (CMP) pad fabricated according to the method using the apparatus of the present invention has a radius and has a surface roughness of at least 0.01 μm to 25 μm (Sq) or preferably 1 μm to 15 μm (Sq). And having a series of visible intersecting arcs on the surface of the polishing layer, and equal to or more than half of the radius of curvature of the polishing layer, preferably equal to half of the radius of curvature of the polishing layer, A porous polymer CMP polishing layer having a radius of curvature is included. Preferably, the series of visible intersecting arcs extends in any way around the surface of the polishing layer in radial symmetry around the center point of the polishing layer.

  A CMP polishing pad made by a method using the apparatus of the present invention has a center point and a radius. Such a polishing pad can have a thickness. Thereby, the pad is tilted to become thicker when the thickness is closer to the center point, or to be thicker when it is further away from the center point.

  Examples: In the following examples, unless otherwise stated, all units of pressure are standard atmospheric pressure (about 101 kPa) and all units of temperature are room temperature (21-23 ° C).

  Example 1 Testing was performed on two types of VP5000 ™ CMP polishing layer or pad (Dow Chemical, Midland, Michigan, Dow) having a radius of 330 mm (13 inches). The pad does not have a window. In Example 1-1, the CMP polishing layer was equipped with a single porous polyurethane pad that was 2.03 mm (80 mils) thick. Here, the polyurethane had a Shore D hardness of 64.9. In Example 1-2, the CMP polishing layer was laminated to a SUBA IV ™ subpad made from polyester felt (Dow) using a pressure sensitive adhesive, the same polyurethane as Example 1-1. A laminated pad having a pad was provided.

  The comparison targets in Examples 1-A and 1-B were the same pads as in Examples 1-1 and 1-2, respectively, but were not processed by the method of the present invention.

  All pads are 1010 grooves (concentric groove pattern with 0.0768 cm (0.030 inch) depth x 0.0511 cm (0.020 inch) width x 0.307 cm (0.120 inch) pitch)) But had no windows.

  The porous abrasive was a vitrified (glass solidified) porous diamond abrasive having an average abrasive size of 151 μm. To grind the substrate, the rotating grinder assembly was placed parallel to the top of the flat bed platen and rotated counterclockwise at 284 rpm, and the aluminum flat bed platen was rotated clockwise at 8 rpm. Beginning at the point where the porous abrasive material just begins to contact the CMP polishing layer substrate, the rotating grinder assembly moves downward toward the flat bed platen at a rate of 5.8 μm (0.0002 inch) every three pad rotations. Sent to. During this time, the compressed dry air (CDA) is disposed at the interface between the surface of the porous abrasive and the CMP polishing layer, and two nozzles (one directly above the center point of the CMP polishing layer and the other is porous). From the center of the pad to about 210 mm (8.25 inches) on the side to which the abrasive material is dragged. Grinding continued for about 5 minutes.

  The pad obtained from Example 1 was evaluated in the following manner in a polishing test for removal rate, non-uniformity, and chatter marks (defects).

Removal rate: The removal rate was measured on a 200 mm tetraethoxysilicate (TEOS) substrate with the indicated pad and ILD3255 ™ fumed silica aqueous slurry (Dow) at a flow rate of 200 ml / min. Used to planarize the substrate. Polishing pressures were 0.11 and 0.21 downward with respect to a platen / substrate carrier having a rotation rate of 93/87 per minute using a Mirra ™ polisher (Applied Materials, Santa Clara, CA). And 0.32 kg / cm ² (1.5, 3.0, 4.5 psi). Prior to testing, all polishing pads were used for 40 minutes using SAESOL ™ 8031C1 disc (blazed diamond powder surface, diameter 10,16 cm, Seasol Diamond Ind. Co., Ltd., Korea) as a conditioner. Adjusted to 3.2 kg (7 pounds). The same condition of the pad continued during the test. All 18 wafers were tested for each pad and the average value was obtained.

  Non-uniformity: Non-uniformity is on the same TEOS substrate flattened in the removal rate test and the removal rate, except that the data was obtained by observing thickness variations in the wafer. Determined in the method disclosed in the study. All 18 wafers were tested for each pad and the average value was obtained.

  Counting of chatter marks or defects; counting of chatter marks or defects is on the same TEOS substrate flattened in the removal rate test and in the removal rate test, except that the data was obtained by observing the total number of CMP defects. Determined in the disclosed method. All 18 wafers were tested for each pad and the average value was obtained.

  The resulting pad had a microtexture on the pad surface that included intersecting arcs with a radius of curvature equal to the radius of the periphery of the rotating grinder assembly. Further, as shown in Table 1 below, the pads according to the present invention of Examples 1-1 and 1-2 were compared with the comparative pads of Examples 1-A (single) and 1-B (laminated). The same planarization rate was given for the substrate. On the other hand, the pads according to the present invention of Examples 1-1 and 1-2 are more than the pads of Examples 1-A and 1-B for comparison in which the grinding method of the present invention was not used. Produced with significantly lower defects and dramatically fewer chatter marks in the substrate.

  Example 2: The test was performed on a large 419 mm (16.5 inch) IC1000 ™ single layer polyurethane pad (Dow) having a Shore D hardness of 61.0. That is, except that the rotating grinder assembly was fed downwards toward the flat bed platen at a rate of 20.3 μm (0.0007 inch) increments every 8 pad revolutions and grinding continued for 5.5 minutes. Was performed with the pad of Example 2 treated in the manner as in Example 1 above. The comparative Example 2-A pad was the same pad as in Example 2 that was not handled according to the method of the present invention.

  The test was performed on 14 pads and average results were reported for the thickness variations tested as follows.

  Thickness variation: Thickness variation was determined using a coordinate measuring device throughout the surface of the polishing pad. A total of nine individual measurement positions from the pad center to the edge were collected for each pad. The thickness variation was calculated by subtracting the thinnest measurement from the thickest measurement. The results are shown in Table 2 below.

  The obtained pad according to the present invention had a fine texture on the surface of the characteristic pad. The inventive pad of Example 2 has less average thickness variation than the comparative Example 2-A pad and is therefore more consistent in shape.

  Example 3: Surface roughness was measured on the pad of Example 2 above compared to the commercially available IC1000 ™ pad (Dow). The pad of Example 2 for comparison was the same pad as in Example 2-A, but was not handled according to the method of the present invention.

  The surface roughness was measured on 5 equally spaced points from the pad center to the edge in each of the two pads, and the average results for the surface roughness are reported in Table 3 below.

  As shown in Table 3 above, the CMP polishing layer of the present invention in Example 3 has a defined surface roughness characterized by a defined pad surface microtexture and reduced valley depth. Have

Claims (11)

An apparatus for providing a preconditioned polymer chemical mechanical (CMP) polishing pad or layer having a fine texture on a pad surface and polishing a substrate,
A rotating grinder assembly having a wheel or rotor having a grinding surface of porous abrasive material;
A flat bed platen for holding the CMP polishing layer in place;
The grinding surface of the rotating grinder is disposed above or parallel to or substantially parallel to the surface of the flat bed platen so as to form an interface between the surface of the CMP polishing layer and the porous abrasive material. Yes,
as well as,
A substrate holder disposed above and in parallel with the upper surface of the flat bed platen so that it does not overlap the area where the rotating grinder assembly is disposed and where the CMP substrate is mounted;
With
Thereby creating a polishing interface between the surface of the substrate and the CMP polishing layer,
The substrate holder rotates independently with respect to the rotating grinder assembly and the flat bed platen;
apparatus.   The apparatus of claim 1, wherein the flat bed platen holds the CMP polishing layer in place by a vacuum.   The CMP polishing layer has a radius extending from its center point to its outer periphery, and the grinding surface of the wheel or rotor of the rotating grinder assembly is equal to or longer than the radius of the CMP polishing layer The apparatus of claim 1 having a diameter.   The apparatus of claim 3, wherein a diameter of the rotating grinder assembly is equal to a radius of the CMP polishing layer.   The apparatus of claim 1, wherein the wheel or rotor of the rotating grinder assembly is positioned such that the outer periphery of its grinding surface is supported directly on the center of the CMP polishing layer during grinding.   The apparatus of claim 1, wherein each of the rotating grinder assembly wheel or rotor, the CMP polishing layer, and the flat bed platen rotate during grinding of the CMP polishing layer. The rotating grinder assembly includes:
A drive housing including a motor or rotary actuator, and a vertically disposed shaft connected to and driven by the motor or rotary actuator, extending into the drive housing and wherein the wheel or rotor is desired per minute 2. The apparatus according to claim 1, further comprising: a shaft connected to the wheel or the rotor via a mechanical coupling portion at a lower end thereof so as to rotate at a speed of a rotation speed of 2 mm. In the drive housing, the vertically arranged shaft is
A ball screw or a second servomotor arranged where the shaft is connected to the motor or rotary actuator;
The mechanical connection of the shaft to the wheel or rotor, or both positions, whereby the wheel or rotor of the rotating grinder assembly can be fed downward at a set incremental speed. The device described. In addition, the compressed inert gas or air is blown intermittently or continuously and so as to act on the porous abrasive during grinding, Comprising a conduit, hose, nozzle, or valve arranged to spray the interface between the surface of the CMP abrasive layer material and the porous abrasive material;
During the grinding, a second conduit, hose, or so as to blow a compressed inert gas or air upwards from a point directly below the periphery of the rotating grinder assembly to act on the porous abrasive The apparatus of claim 1, comprising a valve. The substrate holder has a diameter smaller than the radius of the CMP polishing layer or pad held on the flat bed platen; and
Further, the substrate holder is mechanically coupled or mounted to a first actuator for rotating the grinder about a central axis, and the substrate holder is placed against the CMP polishing layer or pad. The apparatus of claim 1, wherein the apparatus is mechanically coupled or mounted to the second actuator for pressing.   The apparatus of claim 1, wherein the entire apparatus is enclosed in an airtight enclosure.