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  Polishing pad and chemical mechanical polishing apparatus comprising the sameUSPTO Application #: 20080090503Title: Polishing pad and chemical mechanical polishing apparatus comprising the same Abstract: A polishing pad for use in chemically mechanically polishing a semiconductor substrate enhances the uniformity of the rate at which material is removed from the surface of the semiconductor substrate, thereby ensuring the reproducibility of the chemical mechanical polishing process. The polishing pad has main grooves that divide an upper portion of the pad into a plurality of cells. At least one of the cells includes a land portion and a grooved portion substantially enclosed by the land portion. A respective slurry hole extends through the pad to the grooved portion such that slurry supplied through the slurry hole feeds into the grooved portion but is impeded by the land portion from flowing outwardly of the cell. (end of abstract) Agent: Volentine & Whitt PLLC - Reston, VA, US Inventors: Moo-yong PARK, Tae-hoon LEE, Jae-eung KOO USPTO Applicaton #: 20080090503 - Class: 451287000 (USPTO) Related Patent Categories: Abrading, Machine, Rotary Tool, Rotary Disk, Work Rotating, Rotary Work Holder, Planar Surface Abrading The Patent Description & Claims data below is from USPTO Patent Application 20080090503. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This is a divisional of application Ser. No. 11/169,731, filed Jun. 30, 2005, which is incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to a chemical mechanical polishing (CMP) apparatus for polishing a semiconductor substrate. More specifically, the present invention relates to a polishing pad of the of the CMP apparatus. [0004] 2. Description of the Related Art [0005] Recently, the rapid development of data processing and communications technologies has led to the demand for semiconductor devices, such as Dynamic Random Access Memories (DRAMs), that operate rapidly and have large storage capacities. Accordingly, semiconductor device fabrication technology has been developed with the aim of enhancing the integration, reliability, and response speed of semiconductor devices. [0006] Fabricating semiconductor devices that have higher degrees of integration, are more miniaturized, and have large numbers of metal-bearing layers creates larger and larger steps on the surface of the substrates on which the semiconductor devices are formed. Techniques for planarizing the stepped surface of a semiconductor substrate include SOG (Spin On Glass), etch back, and reflow processes. However, chemical mechanical polishing (CMP) has been widely used for globally planarizing a semiconductor substrate surface. Chemical mechanical polishing is carried out by a CMP apparatus using a polishing pad. [0007] FIG. 1 illustrates a conventional polishing pad of a CMP apparatus. Referring to FIG. 1, an upper surface of the conventional polishing pad is formed with grooves 1 and slurry holes 3. A polishing slurry is supplied onto an object to be polished (e.g., a semiconductor substrate) via the slurry holes 3. The slurry is dispersed via the grooves 1. In addition, the polishing pad is rotated during the CMP process. Thus, the slurry is spun off of the peripheral edge of the polishing pad due to the centrifugal force caused by the rotation of the polishing pad during the CMP process. For this reason, the slurry is distributed non-uniformly across the surface of the polishing pad. [0008] Such non-uniform slurry distribution causes variations in the rate at which material is removed across the surface of the semiconductor substrate. In particular, the rate at which material is removed by the polishing process at the center of the semiconductor substrate is remarkably different from the rate at which material is removed at the periphery of the semiconductor substrate. The planarity of the semiconductor substrate depends on the uniformity of the removal rate. Thus, the conventional polishing pad makes it difficult to planarize a semiconductor substrate sufficiently and to effect a CMP process that is reproducible. SUMMARY OF THE INVENTION [0009] An object of the present invention is to provide a polishing pad of a chemical mechanical polishing (CMP) apparatus that enhances the uniformity of the rate at which material is removed from a substrate being polished, thereby ensuring the reproducibility of the CMP process. [0010] According to one aspect of the present invention, there is provided a polishing pad for use in chemical mechanical polishing, the polishing pad having an upper surface, main grooves extending in the upper surface and separating an upper portion of the pad into a plurality of cells, and wherein at least one of the cells consists of a land portion and a grooved portion. The grooved portion is substantially enclosed by the land portion and is defined by at least one groove extending in the upper surface of the pad within the cell. [0011] A respective slurry hole extends through the pad to the grooved portion of the cell(s). Thus, slurry supplied through the slurry hole towards the upper surface of the pad will feed into the at least one groove and will be impeded by the land portion from spreading outwardly of the cell. [0012] According to another aspect of the present invention, there is provided a polishing pad for use in chemical mechanical polishing, the polishing pad having an upper surface, main grooves extending in the upper surface and separating an upper portion of the pad into a plurality of cells, and wherein at least one of the cells consists of a land portion, and a grooved portion defined by at least a first major groove and at least one minor groove extending in the upper surface of the pad. [0013] A respective slurry hole extends through the pad to the first major groove. Each one minor groove has a closed geometric shape and is connected to the first major groove. Thus, slurry supplied through the slurry hole towards the upper surface of the pad will be fed to the minor groove via the first major groove. Also, the cross-sectional area of each minor groove is smaller than that of the first major groove to thereby regulate the flow of the slurry from the first major groove. [0014] According to still another aspect of the present invention, there is provided a chemical mechanical polishing apparatus including a polishing pad. BRIEF DESCRIPTION OF THE DRAWINGS [0015] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments thereof made with reference to the attached drawings in which: [0016] FIG. 1 is a plan view of a conventional polishing pad for use in the chemical mechanical polishing (CMP) of a semiconductor substrate; [0017] FIG. 2 is a schematic diagram of a CMP apparatus for polishing a semiconductor substrate using a polishing pad according to the present invention; [0018] FIG. 3 is a plan view of a first embodiment of a polishing pad of the CMP apparatus according to the present invention; [0019] FIG. 4 is a plan view of a modified form of the first embodiment of the polishing pad according to the present invention; [0020] FIG. 5 is a plan view of a second embodiment of a polishing pad of CMP apparatus according to the present invention; Continue reading... Full patent description for Polishing pad and chemical mechanical polishing apparatus comprising the same Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Polishing pad and chemical mechanical polishing apparatus comprising the same patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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