| Method for conditioning a polishing pad -> Monitor Keywords |
|
|
  Method for conditioning a polishing padUSPTO Application #: 20080020682Title: Method for conditioning a polishing pad Abstract: A method of conditioning processing pads increases the removal rate of conductive material from a substrate surface during polishing. In this method, the direction of rotation of the processing pad relative to the conditioning disc during conditioning is opposite the direction of rotation of the processing pad relative to the substrate during polishing. (end of abstract)
Agent: Patterson & Sheridan, LLP - Houston, TX, US Inventors: Renhe Jia, Jie Diao, You Wang, Stan D. Tsai, Jim K. Atkinson, Lakshmanan Karuppiah, Liang-Yuh Chen USPTO Applicaton #: 20080020682 - Class: 451056000 (USPTO) Related Patent Categories: Abrading, Abrading Process, With Tool Treating Or Forming The Patent Description & Claims data below is from USPTO Patent Application 20080020682. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] Embodiments of the present invention generally relate to the fabrication of integrated circuits and more particularly to the removal of conductive material from a substrate. [0003] 2. Description of the Related Art [0004] In VLSI and ULSI semiconductor manufacturing, reliable formation of multilevel interconnects is important to the continued effort to increase circuit density and quality of individual substrates and die. Multilevel interconnects are formed using sequential material deposition and material removal techniques on a substrate surface to form features therein. As layers of materials are sequentially deposited and removed, the uppermost surface of the substrate may become non-planar across its surface and require planarization prior to further processing. Planarization, or "polishing," is a process in which material is removed from the surface of the substrate to form a generally even, planar surface. Planarization is useful in removing excess deposited material, undesired surface topography, and surface defects, such as surface roughness, agglomerated materials, crystal lattice damage, scratches, and the like. Planarization also provides an even surface for subsequent photolithography and other semiconductor manufacturing processes. [0005] Electrochemical mechanical polishing (ECMP) is one method of planarizing a surface of a substrate. ECMP is a method that removes conductive materials, such as copper, from a substrate surface by electrochemical "anodic" dissolution while polishing the substrate with a reduced mechanical abrasion and pressure compared to conventional chemical mechanical planarization (CMP) processes. The greatly reduced down-pressure required for ECMP allows the planarization of substrates having delicate low-k materials deposited thereon. Electrochemical dissolution is performed by applying an electrical bias between a cathode and a substrate surface to remove conductive materials from the substrate surface into a surrounding electrolyte, such as a polishing composition. The bias may be applied to the substrate surface by a conductive contact disposed on or through a polishing material upon which the substrate is processed. The polishing material may be, for example, a processing pad disposed on a rotating platen. The polishing composition may be disposed in the processing pad and the metal ions on the substrate surface dissolve into the surrounding polishing composition. [0006] A typical ECMP system includes a substrate support and two electrodes disposed within an electrolyte containment basin. The substrate is in electrical contact with one of the electrodes, and in effect, the substrate becomes an anode during processing for material removal. A mechanical component of the polishing process is performed by providing a relative motion between the substrate and the processing pad while in contact with each other that enhances the removal of the conductive material from the substrate. [0007] The removal rate of conductive material from a substrate surface is an important metric for the performance of an ECMP processing system. Lower removal rate results in a longer processing time, thereby increasing the production cost per substrate. Process parameters used to affect removal rate during ECMP include voltage applied between the electrodes, makeup of electrolyte/polishing composition, substrate pressure against the processing pad, polishing head rpm, and processing pad rpm. [0008] Conventionally an abrasive conditioning element, such as a diamond conditioning disk, or a brush conditioner, such as a Nylon.TM. brush, is periodically used to refurbish the processing pad surface to improve polishing results. A conditioning element is applied to the processing pad, often in conjunction with a suitable cleaning fluid, using a spinning conditioning disc that also translates laterally across the surface of the processing pad. After such conditioning, the removal rate of the processing pad is increased and fewer substrate surface defects are formed by the processing pad. A conditioning process is also typically performed on unused processing pads in order to remove native oxides and other passivation layers formed on the conductive materials therein in order to "break-in" the processing pad. [0009] FIG. 1 is a schematic plan view of an ECMP processing station 100, having a rotating substrate polishing head 101, a processing pad 103 disposed on a rotating platen (not shown) and a conditioning head 104 disposed on a swing arm 105. In addition to rotation, polishing head 101 is also typically adapted to translate linearly or curvilinearly across processing pad 103 during ECMP processing. [0010] ECMP processing station 100 performs both substrate processing and processing pad conditioning. In operation, a substrate is mounted on polishing head 101 and is processed face-down, i.e., production side down, during the ECMP process. Polishing head 101 and processing pad 103 rotate continuously in one direction, in this example counterclockwise. Polishing head 101 may also translate linearly across the surface of processing pad 103. During processing pad conditioning, processing pad 103 continues to rotate in the same direction as during the ECMP process, and conditioning head 104 rotates continuously in that same direction. Conditioning head 104 is also displaced along path 120 in a sweeping motion during the conditioning process to uniformly and completely condition the entire surface of processing pad 103. [0011] While the processing pad conditioning method described above improves the removal rate of ECMP processing pads, even higher removal rates are desirable in the ECMP process. Higher ECMP removal rates result in higher throughput and, and hence, lower processing cost per substrate. In addition, higher ECMP removal rates for a given processing pad allow more substrates to be processed before reconditioning of the pad is necessary. Because the reconditioning process is generally time-consuming, a longer period between such reconditioning significantly reduces ECMP system downtime, which also lowers processing cost per substrate. SUMMARY OF THE INVENTION [0012] The present invention provides a method of conditioning processing pads that increases the removal rate. According to embodiments of the present invention, conductive material removal rates will be increased during the ECMP process if the direction of rotation of the processing pad relative to the conditioning disc is opposite the direction of rotation of the processing pad relative to the substrate. [0013] According to a first embodiment, the relative rotation between the conditioning element and the processing pad is produced by rotating both the conditioning element and the processing pad in a first rotational direction. The relative rotation between the substrate and the processing pad during polishing is produced by rotating both the substrate and the processing pad in a second rotational direction, wherein the second rotational direction is opposite to the first rotational direction. [0014] According to a second embodiment, the relative rotation between the conditioning element and the processing pad is produced by rotating the processing pad in a first rotational direction and the relative rotation between the substrate and the processing pad is produced by rotating the processing pad in a second rotational direction, wherein the second rotational direction is opposite to the first rotational direction. [0015] According to a third embodiment, the relative rotation between the conditioning element and the processing pad is produced by rotating the conditioning element in a first rotational direction and rotating the processing pad in a second rotational direction, wherein the first rotational direction is the opposite of the second rotational direction. The relative rotation between the substrate and the processing pad during polishing is produced by rotating the substrate in the second rotational direction and the processing pad in the first rotational direction. [0016] According to a fourth embodiment, the relative rotation between the conditioning element and the processing pad is produced by rotating one of the conditioning element or the processing pad in a first rotational direction while the other remains rotationally stationary. The relative rotation between the substrate and the processing pad during polishing is produced by rotating one of the substrate or the processing pad in a second rotational direction while the other remains rotationally stationary, wherein the first rotational direction is the opposite of the second rotational direction. BRIEF DESCRIPTION OF THE DRAWINGS [0017] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. [0018] FIG. 1 (Prior Art) is a schematic plan view of an ECMP processing station. [0019] FIG. 2 is a cross-sectional view of one example of an ECMP station that may benefit from aspects of the invention. [0020] FIG. 3 is a schematic plan view of an exemplary planarization platform. [0021] FIG. 4 is a schematic plan view of an ECMP processing station. Continue reading... Full patent description for Method for conditioning a polishing pad Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method for conditioning a polishing pad 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. Start now! - Receive info on patent apps like Method for conditioning a polishing pad or other areas of interest. ### Previous Patent Application: Knife sharpening method and system Next Patent Application: Polishing method and polishing pad Industry Class: Abrading ### FreshPatents.com Support Thank you for viewing the Method for conditioning a polishing pad patent info. IP-related news and info Results in 0.28475 seconds Other interesting Feshpatents.com categories: Accenture , Agouron Pharmaceuticals , Amgen , AT&T , Bausch & Lomb , Callaway Golf |
||
