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  Deposition technique to planarize a multi-layer structureUSPTO Application #: 20070077763Title: Deposition technique to planarize a multi-layer structure Abstract: The present invention is directed to a method of coating a substrate having a solidified layer formed thereon, that features depositing a flowable material upon the solidified layer and forming an additional layer having a smooth flowable surface upon the substrate by imparting rotational movement upon the substrate followed by leveling of the flowable material in an absence of the rotational movement. After the additional layer is formed, the same is solidified. (end of abstract) Agent: Molecular Imprints - Austin, TX, US Inventors: Frank Y. Xu, Edward B. Fletcher USPTO Applicaton #: 20070077763 - Class: 438689000 (USPTO) Related Patent Categories: Semiconductor Device Manufacturing: Process, Chemical Etching The Patent Description & Claims data below is from USPTO Patent Application 20070077763. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] The present application is a divisional of U.S. patent application Ser. No. xx/xxx,xxx (Attorney Docket No. P234M1D238) filed herewith, entitled ETCHING TECHNIQUE TO PLANARIZE A MULTI-LAYER STRUCTURE, listing David C. Wang and Frank Y. Xu as inventors, which application is incorporated by reference herein. BACKGROUND OF THE INVENTION [0003] This invention relates to spin-on coating of substrates. Specifically, the present invention is directed to a method to coat a substrate employing spin-on techniques in furtherance of lithographic patterning. [0004] Spin-coating is a well known technique employed to form a layer of material upon a substrate. Often the material is deposited upon a surface having anisotropic topography in furtherance of producing a film having a planar surface disposed opposite to the substrate surface. The planarity of the material surface is highly desirable for several processes, e.g., deposition of resist material in furtherance of patterning. As a result, studies have been undertaken to understand the behavior of films formed during spin-coating. Peurrung and Graves in Film Thickness Profiles over Topography in Spin Coating, Journal of the Electrochemical Society, Vol. 138 No. 7 (1991), set forth a theoretical analysis of spin-coating wet films over anisotropic surfaces. Peurrung and Graves conclude that the presence of anisotropicity of the substrate surface makes problematic production of a planar material surface. Many attempts have been undertaken to obtain a planar material surface from material spin-coated on an anisotropic surface. [0005] U.S. Pat. No. 4,038,110 discloses a technique to planarize an anisotropic substrate surface involves forming a photoresist pattern in registration that with a pattern of unelevated areas present on the substrate. The photoresist pattern has narrower lateral dimensions than an elevated pattern whereby registration is facilitated. The photoresist pattern is flowed to laterally expand the photoresist and mask the unelevated areas. [0006] In U.S. Pat. No. 4,741,926, one manner in which to overcome the drawbacks with multi-layer resists involve spreading a resin material over an anisotropic surface employing a dual spin cycle. The resin material is spread at a speed of approximately of not less than 4000 revolutions per minute (rpm), preferably from 6000 to 8000 rpm, until build-up of the coating is detectable on a side wall of a topographical feature facing the centrifugal center of the spinning substrate. The spin speed is immediately reduced to less than 4000 rpm, preferably from about 1000 to 3500 rpm, and spinning is continued for a time sufficient to dry the coating. [0007] U.S. Pat. No. 4,794,021 discloses a method of forming a planarized layer on a substrate by spin coating a polymer over the substrate. Before the layer dries the substrate is heated in a pressure-controlled environment to control solvent loss while maintaining the polymer in a liquid-state. After a predetermined interval of time, the substrate is cured in a standard convention bake oven. [0008] U.S. Pat. No. 5,736,424 discloses a method that includes contacting a material having a predetermined viscosity with an object having a flat surface. The material has a viscosity less than 1000 cp, and a flat surface is placed into contact with the material in such a manner that the material is planarized to a desired degree. The material is cured while in contact with the flat surface. The object is then separated from the material. The planarity of the planarizing material is then transferred into the underlying layer using conventional techniques. [0009] U.S. Pat. No. 5,893,750 discloses a method of forming a planarized interlevel dielectric layer over interconnects formed upon a frontside surface of an upper topography of a silicon wafer. An anisotropic silicon dioxide (oxide) layer is first deposited over the interconnects. A spin-on glass (SOG) layer is then formed over the anisotropic oxide layer. The liquid SOG material flows over the upper surface, filling narrow spaces without creating voids and producing a surface smoothing effect at isolated vertical edges. After curing of the SOG layer, a chemical-mechanical polishing (CMP) process is applied to the frontside surface. The CMP process increases the planarity of the frontside surface by reducing surface heights of elevated features more so than surface heights in recessed areas. A need exists, however, to provide improved planarization techniques. SUMMARY OF THE INVENTION [0010] The present invention is directed to a method of coating a substrate having a solidified layer formed thereon, that features depositing a flowable material upon the solidified layer and forming an additional layer having a smooth flowable surface upon the substrate by imparting rotational movement upon the substrate followed by leveling of the flowable material in an absence of the rotational movement. After the additional layer is formed, the same is solidified. These and other embodiments are discussed more fully below. BRIEF DESCRIPTION OF THE DRAWINGS [0011] FIG. 1 is a cross-sectional view of a substrate having an anisotropic surface that is to be planarized in accordance with the present invention; [0012] FIG. 2 is a cross-sectional view of the substrate shown in FIG. 1 having a planarized surface, in accordance with the present invention; [0013] FIG. 3 is a cross-sectional view of the substrate shown in FIG. 1 having a semi-conformal layer deposited therein; [0014] FIG. 4 is a detailed cross-sectional view of a region of the substrate shown in FIG. 3; [0015] FIG. 5 is a cross-sectional view of the substrate shown in FIG. 4 having a smoothing layer deposited thereon; [0016] FIG. 6 is a cross-sectional view of a prior art etching chamber; [0017] FIG. 7 is a cross-sectional view of substrate shown in FIG. 5 after being etched employing first etch conditions in accordance with the present invention; [0018] FIG. 8 is a cross-sectional view of substrate shown in FIG. 7 after being etched employing second etch conditions in accordance with the present invention; DETAILED DESCRIPTION OF THE INVENTION [0019] Referring to FIG. 1, in certain patterning processes it is desired to form a planar surface upon substrates, such as substrate 10, having an anisotropic surface. The anisotropic surface may include spaced-apart projections 14 and 16, defining spaced-apart recessions 18, which may result from any known previous patterning process. Projections 14 may be metal lines, photoresist, monocrystalline silicon and the like. In the present example, substrate 10 is discussed as including a wafer 20 formed from standard materials, e.g., mono-crystalline silicon. Present upon wafer 20 is a patterned layer 22 in which projections 14 and 16 are formed. In the present example it is desired to form a planarized surface, referred to as a crown surface 25, in which substantially the entire surface area of an apex surface 24 of projections 14 and substantially the entire surface area of an apex surface 26 of projections 16 are exposed and coplanar with a surface 28 of a material deposited to fill recessions 18. To that end, in an exemplary embodiment, patterned layer 22 is formed from a solidified polymeric material employing imprint lithography techniques, with a primer layer 23 being disposed between patterned layer and wafer 20. Primer layer 23 is typically formed from spin-coating a layer of DUV30J-16. DUV30J-16 is a bottom anti-reflective coating, BARC, available from Brewer Science in Rolla, Mo. An exemplary bulk material from which to form patterned layer 22 is as follows: Patterned Layer Bulk Imprinting Material Continue reading... Full patent description for Deposition technique to planarize a multi-layer structure Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Deposition technique to planarize a multi-layer structure 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 Deposition technique to planarize a multi-layer structure or other areas of interest. ### Previous Patent Application: Technique for forming a copper-based metallization layer including a conductive capping layer Next Patent Application: Polishing method, polishing composition and polishing composition kit Industry Class: Semiconductor device manufacturing: process ### FreshPatents.com Support Thank you for viewing the Deposition technique to planarize a multi-layer structure patent info. IP-related news and info Results in 2.6582 seconds Other interesting Feshpatents.com categories: Computers: Graphics , I/O , Processors , Dyn. Storage , Static Storage , Printers |
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