| Friction reducing aid for cmp -> Monitor Keywords |
|
|
  Friction reducing aid for cmpRelated Patent Categories: Abrading, Abrading Process, Glass Or Stone AbradingThe Patent Description & Claims data below is from USPTO Patent Application 20070117497. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] Integrated circuits are made up of millions of active devices formed in or on a substrate, such as a silicon wafer. The active devices are chemically and physically connected into a substrate and are interconnected through the use of multilevel interconnects to form functional circuits. In one manufacturing process, a dielectric substrate is patterned by a conventional dry etch process to form holes and trenches for vertical and horizontal interconnects. The patterned surface is then optionally coated with a diffusion barrier layer and/or an adhesion-promoting layer, followed by deposition of a metal layer to fill the trenches and holes. Chemical-mechanical polishing (CMP) is then employed to reduce the thickness of the metal layer, as well as the thickness of the diffusion barrier layer and/or adhesion-promoting layer, until the underlying dielectric layer is exposed, thus forming the circuit device. [0002] In chemical-mechanical polishing, the surface of the substrate is contacted with a polishing composition and a polishing component, such as a polishing pad. Polishing compositions (also known as polishing slurries) typically contain an abrasive material in an aqueous solution and are applied to a surface by contacting the surface with a polishing pad saturated with the polishing composition. Chemical components of the polishing compositions are thought to react with surface materials of the substrate being polished, either by converting the surface materials to softer, more easily abradable derivatives of the materials, which derivatives are then removed by mechanical action of the abrasive material and/or the polishing pad, or by solubilizing the surface materials that are removed by mechanical action alone. In certain applications, the abrasive can be affixed to the surface of the polishing pad. [0003] The frictional forces resulting from the relative motion of the substrate surface and the surface of the polishing pad with a polishing composition therebetween during the polishing process can lead to defectivity of the device being formed on the substrate via damage of the lines by scratching of the substrate by abrasive particles and/or the polishing pad and via delamination of the surface layers from the substrate. In addition, frictional heating of the polishing pad at the pad/slurry interface can lead to premature pad failure. Strategies to reduce frictional forces, such as incorporation of surfactants into polishing compositions, use of polishing pads composed of softer materials, or reduction of force applied to the substrate/polishing pad interface often result in the reduction of removal rates of the materials being polished, which can result in increased processing times, thus reducing throughput and increasing overall unit costs. [0004] Further, in efforts to reduce the capacitance between conductive layers on microelectronic devices and thus to increase the frequency or speed at which the devices can operate, materials having lower dielectric constants than the commonly used silicon dioxide-based dielectrics are being employed to provide electrical isolation between circuit lines. Examples of low dielectric constant materials typically include organic polymer materials, inorganic and organic porous dielectric materials, and blended or composite organic and inorganic materials, which can be porous or non-porous. Such materials are mechanically softer than silicon dioxide-based dielectrics and are more easily damaged during device manufacture. It would be highly desirable to incorporate low dielectric constant materials into semiconductor structures while still being able to utilize the conventional chemical-mechanical polishing (CMP) systems for polishing the surface of the resulting devices during semiconductor wafer processing. [0005] Thus, a need remains for chemical-mechanical polishing compositions and systems exhibiting reduced friction between substrates and polishing components. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein. BRIEF SUMMARY OF THE INVENTION [0006] The invention provides a chemical-mechanical polishing system for polishing a substrate comprising (a) a polishing component selected from the group consisting of a polishing pad, an abrasive, and a combination thereof, (b) a water-soluble silicate compound in an amount sufficient to provide about 0.1 wt. % or more of SiO.sub.2, (c) an oxidizing agent that oxidizes at least part of a substrate, and (d) water, wherein the pH of the polishing system is about 8 to about 12. The invention further provides a method of chemically-mechanically polishing a substrate, which method comprises (i) contacting a substrate with a chemical-mechanical polishing system comprising (a) a polishing component selected from the group consisting of a polishing pad, an abrasive, and a combination thereof, (b) a water-soluble silicate compound in an amount sufficient to provide about 0.1 wt. % or more of SiO.sub.2, (c) an oxidizing agent that oxidizes at least part of a substrate, and (d) water, and (ii) abrading at least a portion of the substrate to polish the substrate, wherein the pH of the polishing system is about 8 to about 12. BRIEF DESCRIPTION OF THE DRAWING [0007] The Figure illustrates a method for determination of the coefficient of friction for a chemical-mechanical polishing process. DETAILED DESCRIPTION OF THE INVENTION [0008] The invention provides a chemical-mechanical polishing (CMP) system comprising a polishing component, a water-soluble silicate compound in an amount sufficient to provide about 0.1 wt. % or more of SiO.sub.2, an oxidizing agent that oxidizes at least part of a substrate, and water, wherein the pH of the polishing system is about 8 to about 12. The water and any components dissolved or suspended therein form the polishing composition of the chemical-mechanical polishing system. The amounts of the components recited herein are based on the total weight of the polishing composition unless otherwise noted (i.e., the weight of the water and any components dissolved or suspended therein). [0009] The polishing component is selected from the group consisting of a polishing pad, an abrasive, and the combination of a polishing pad and an abrasive. If an abrasive is present, the abrasive can be in any suitable form (e.g., abrasive particles). The abrasive can be fixed on the polishing pad and/or can be in particulate form and suspended in the water. The polishing pad can be any suitable polishing pad, many of which are known in the art. [0010] The abrasive can be any suitable abrasive, for example, the abrasive can be natural or synthetic, and can comprise metal oxide, carbide, nitride, carborundum, and the like. The abrasive also can be a polymer particle or a coated particle. The abrasive desirably comprises a metal oxide. Preferably, the metal oxide is selected from the group consisting of alumina, ceria, silica, zirconia, co-formed products thereof, and combinations thereof. The abrasive particles typically have an average particle size (e.g., average particle diameter) of about 20 nm to about 500 nm. Preferably, the abrasive particles have an average particle size of about 30 nm to about 400 mn (e.g., about 40 nm to about 300 [0011] mn, or about 50 mn to about 250 nm, or about 75 nm to about 200 nm). [0012] When the abrasive is suspended in the water (i.e., when the abrasive is a component of the polishing composition), any suitable amount of abrasive can be present in the polishing composition. Typically, about 0.01 wt. % or more (e.g., about 0.05 wt. % or more) abrasive will be present in the polishing composition. More typically, about 0.1 wt. % or more abrasive will be present in the polishing composition. The amount of abrasive in the polishing composition typically will not exceed about 20 wt. %, more typically will not exceed about 10 wt. % (e.g., will not exceed about 5 wt. %). Preferably, the amount of abrasive in the polishing composition is about 0.05 wt. % to about 2 wt. %, and more preferably about 0.1 wt. % to about 1 wt. %. [0013] The polishing system can comprise any suitable polishing pad (e.g., polishing surface). Suitable polishing pads include, for example, woven and non-woven polishing pads. Moreover, suitable polishing pads can comprise any suitable polymer of varying density, hardness, thickness, compressibility, ability to rebound upon compression, and compression modulus. Suitable polymers include, for example, polyvinylchloride, polyvinylfluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, coformed products thereof, and mixtures thereof. [0014] The polishing system comprises a water-soluble silicate compound. The water-soluble silicate compound can be any suitable water-soluble silicate compound. Desirably, the water-soluble silicate compound is an alkali metal silicate. Preferably, the water-soluble silicate compound is selected from the group consisting of potassium silicate, sodium silicate, potassium metasilicate, and sodium metasilicate. More preferably, the water-soluble silicate compound is potassium silicate. [0015] Water-soluble silicate compounds suitable for use in the invention can be silicate glasses. Silicate glasses are typically prepared by high-temperature fusion of silica sand with a suitable alkali metal compound (e.g., sodium carbonate or potassium carbonate). [0016] Water-soluble silicates have the general formula M.sub.2O.mSiO.sub.2.nH.sub.2O, where M is an alkali metal selected from the group consisting of sodium, potassium and lithium, and m, referred to as the modulus, and n are the number of moles of SiO.sub.2 and H.sub.2O, respectively, per mole of M.sub.2O. The modulus m is the molar ratio of SiO.sub.2 to M.sub.2O. The weight ratio of SiO.sub.2 to M.sub.2O is also commonly used to describe the composition of water-soluble alkali metal silicates. The modulus m can be any suitable positive nonzero number (e.g., about 1 or more), typically about 1 to about 4, and more typically about 2 to about 4 (e.g., about 2.8 to about 3.9, or about 3 to about 3.6). [0017] In a preferred embodiment, the water-soluble silicate compound is potassium silicate having a general formula K.sub.2O.mSiO.sub.2 wherein the modulus m (e.g., the molar ratio of SiO.sub.2 to K.sub.2O) is a positive nonzero number. The potassium silicate can have any suitable modulus. Desirably, the modulus is about 1 or more. Preferably, the modulus is about 2.8 to about 3.9. More preferably, the modulus is about 3 to about 3.6. [0018] The water-soluble silicate compound is present in aqueous solution in the polishing composition. A method of providing the water-soluble silicate compound is to dissolve a solid form of the water-soluble silicate compound in water to provide a solution. Alternatively, a concentrated solution of the water-soluble silicate compound can be diluted to obtain the desired concentration of the water-soluble silicate compound in solution. Various grades of potassium silicate and sodium silicate solutions in water are available commercially, wherein the solutions are characterized by the particular modulus of the silicates used in their preparation, as well as wt. % SiO.sub.2 and wt. % K.sub.2O or Na.sub.2O of the solutions. Zaclon, Inc. (Cleveland, Ohio) and PQ Corporation (Valley Forge, Pa.) are two major suppliers of both solid forms and solutions of potassium silicate and sodium silicate. [0019] Aqueous solutions of potassium silicate also can be obtained by hydrothermal processes, wherein a silicon dioxide (e.g., SiO.sub.2) source is reacted with aqueous solutions of potassium hydroxide under conditions of elevated temperature and/or pressure. Examples of suitable hydrothermal processes for production of aqueous solutions of potassium silicate are disclosed in U.S. Pat. Nos. 5,084,262 and 5,238,668. [0020] The polishing composition of the polishing system can comprise any suitable amount of the water-soluble silicate compound. Generally, the content of the water-soluble silicate compound present in the polishing composition is expressed as the weight percent of SiO.sub.2 provided by the water-soluble silicate compound, based on the total weight of water and any components dissolved therein. It will be understood that the formula "SiO.sub.2" is a formal representation to allow for the calculation of the amount of water-soluble silicate compound useful in the polishing composition regardless of the source thereof (e.g., aqueous solutions or solid forms of water-soluble silicate compounds of various compositions as described herein). Typically, the polishing composition comprises sufficient water-soluble silicate compound to provide about 0.1 wt. % or more (e.g., about 0.25 wt. % or more, about 0.5 wt. % or more, about 1 wt. % or more, about 1.5 wt. % or more, or about 2 wt. % or more) of SiO.sub.2. The polishing composition preferably comprises sufficient water-soluble silicate compound to provide about 8 wt. % or less (e.g., about 6 wt. % or less, or about 4 wt. % or less, or even about 3 wt. % or less) of SiO.sub.2. The polishing composition most preferably comprises about 0.25 wt. % to about 5 wt. % (e.g., about 0.5 wt. % to about 4 wt. %, or about 1 wt. % to about 3 wt. %) of SiO.sub.2. Continue reading... Full patent description for Friction reducing aid for cmp Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Friction reducing aid for cmp 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 Friction reducing aid for cmp or other areas of interest. ### Previous Patent Application: Method for preparing decorative elements Next Patent Application: Apparatus at a flat card or roller card for grinding a clothing drawn onto a rotating roller Industry Class: Abrading ### FreshPatents.com Support Thank you for viewing the Friction reducing aid for cmp patent info. IP-related news and info Results in 0.44609 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers |
||
