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  Back-biased face target sputtering based memory with low oxygen flow rateUSPTO Application #: 20070007124Title: Back-biased face target sputtering based memory with low oxygen flow rate Abstract: Systems and methods are disclosed to form an exemplary memory structure by flowing argon gas and oxygen gas in a deposition chamber; providing a low oxygen flow rate approximately between 0 and ten percent (10%) of an argon flow rate, a pressure approximately between 2×10−5 Torr and 1×10−3 Torr, and a deposition temperature approximately between 340° C. and 450° C.; and the composition of sputtering target is PCMO (Pr1-xCaXMnO3, where X is between 0.1 and 0.9). The process forms a PCMO (Pr1-xCaXMnO3, X=0.1-0.9) material film on the wafer. (end of abstract) Agent: Tran & Associates - San Jose, CA, US Inventor: Makoto Nagashima USPTO Applicaton #: 20070007124 - Class: 204192150 (USPTO) Related Patent Categories: Chemistry: Electrical And Wave Energy, Non-distilling Bottoms Treatment, Coating, Forming Or Etching By Sputtering, Glow Discharge Sputter Deposition (e.g., Cathode Sputtering, Etc.), Specified Deposition Material Or Use The Patent Description & Claims data below is from USPTO Patent Application 20070007124. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] This application is a continuation in part (CIP) application of Ser. No. 10/662,862, the content of which is incorporated by reference. BACKGROUND [0002] The present invention relates to systems and methods for fabricating semiconductor devices at low temperature. [0003] Electronic systems have become a ubiquitous fixture in modern society. These electronic systems range from simple, hand-held calculators to more complex systems including computers, personal digital assistants (PDAs), embedded controllers and complex satellite imaging and communications systems. As noted in U.S. Pat. No. 6,862,211, many electronic systems include a microprocessor that performs one or more functions based on data provided to the microprocessor. This data is typically stored in a memory device of the electronic system such as a common dynamic random access memory (DRAM) device. A DRAM typically includes an array of memory cells that store data as binary values, e.g., 1's and 0's. In a conventional DRAM, the data is stored by controlling the charge on capacitors in each cell of the DRAM. Data in the array is "randomly accessible" since a processor can retrieve data from any location in memory by providing the appropriate address to the memory device. One problem with conventional DRAM is that the device is "volatile." This means that when power is turned off to the system using the DRAM, the data in the memory device is lost. [0004] In a parallel trend, various semiconductor fabrication steps need to be done at low temperature. For instance, when applying a ferroelectric thin film to a highly integrated device, conventional processes do not provide a ferroelectric thin film which sufficiently fulfills various conditions, such as denseness and evenness on the thin film surface required for fine processing and formation of film at a relatively low temperature. [0005] U.S. Pat. No. 5,000,834 discloses a vacuum deposition technique known as face target sputtering to form thin films on magnetic recording heads at low temperature. The sputtering method is widely used for forming a thin film on a substrate made of PMMA because of intimacy between the substrate and the thin film formed therethrough. The amorphous thin film of rare earth--transition metal alloy formed through the sputtering method is applied to an erasable magneto-optical recording medium. The sputtering method is performed as follows: Positive ions of an inert gas such as Argon (Ar) first created by a glow discharge are accelerated toward a cathode or target, and then they impinge upon the target. As a result of ionic bombardment, neutral atoms and ions are removed from the target surface into a vacuum chamber due to the exchange of momentum therebetween. The liberated or sputtered atoms and ions are consequently deposited on a preselected substrate disposed in the vacuum chamber. [0006] U.S. Pat. No. 6,156,172 discloses a plasma generating unit and a compact configuration of the combination of plasma space and substrate holders for a facing target type sputtering apparatus which includes: an arrangement for defining box-type plasma units supplied therein with sputtering gas mounted on outside wall-plates of a closed vacuum vessel; at least a pair of targets arranged to be spaced apart from and face one another within the box-type plasma unit, with each of the targets having a sputtering surface thereof; a framework for holding five planes of the targets or a pair of facing targets and three plate-like members providing the box-type plasma unit so as to define a predetermined space apart from the pair of facing targets and the plate-like members, which framework is capable of being removably mounted on the outside walls of the vacuum vessel with vacuum seals; a holder for the target having conduits for a coolant; an electric power source for the targets to cause sputtering from the surfaces of the targets; permanent magnets arranged around each of the pair of targets for generating at least a perpendicular magnetic field extending in a direction perpendicular to the sputtering surfaces of the facing targets; devices for containing the permanent magnets with target holders, removably mounted on the framework; and a substrate holder at a position adjacent the outlet space of the sputtering plasma unit in the vacuum vessel. The unified configuration composed of a cooling device for cooling both the backside plane of the targets and a container of magnets in connection with the framework improves the compactness of sputtering apparatus. SUMMARY [0007] In one aspect, systems and methods are disclosed to form an exemplary memory structure by flowing argon gas and oxygen gas in a deposition chamber; providing a low oxygen flow rate approximately between 0 and ten percent (10%) of an argon flow rate, a pressure approximately between 2.times.10.sup.-5 Torr and 1.times.10.sup.-3 Torr, and a deposition temperature approximately between 340.degree. C. and 450.degree. C.; and forming a PCMO (Pr.sub.1-xCa.sub.XMnO.sub.3, where X is approximately between 0.1 and 0.9) material. [0008] Implementations of the above aspect may include one or more of the following. The PCMO material maintains a uniform ratio of Pr:Ca:Mn:O is across the PCMO material. A poly-crystalline PCMO can be formed at a temperature below 400.degree. C. with the low oxygen flow rate. A memory device can be formed. The PCMO structure includes a layer of with a thickness of 2,000 .ANG. or less. Materials can be deposited using a radio frequency (RF) rate of 13.56 Megahertz. The method includes providing at least one target and a substrate having a film-forming surface portion and a back portion; creating a magnetic field so that the film-forming surface portion is placed in the magnetic field with the magnetic field induced normal to the substrate surface portion; back-biasing the back portion of the substrate; and sputtering material onto the film-forming surface portion, wherein the thin forming surface portion comprises non-volatile data storage devices interconnected thereto. [0009] In another aspect, a facing targets sputtering device for semiconductor fabrication includes an air-tight chamber in which an inert gas is admittable and exhaustible; a pair of target plates placed at opposite ends of said air-tight chamber respectively so as to face each other and form a plasma region therebetween; a pair of magnets respectively disposed adjacent to said target plates such that magnet poles of different polarities face each other across said plasma region thereby to establish a magnetic field of said plasma region between said target plates; a substrate holder disposed adjacent to said plasma region, said substrate holder adapted to hold a substrate on which an alloyed thin film is to be deposited; and a back-bias power supply coupled to the substrate holder. [0010] In another aspect, a method for sputtering a thin film onto a substrate includes providing at least one target and a substrate having a film-forming surface portion and a back portion; creating a magnetic field so that the film-forming surface portion is placed in the magnetic field with the magnetic field induced normal to the substrate surface portion; back-biasing the back portion of the substrate; and sputtering material onto the film-forming surface portion. [0011] Advantages of the invention may include one or more of the following. The substrate temperature in forming a thin film is approximately below 400 degrees C. and the process requires a short time. Since the thin film is formed at a very low temperature during substantially the whole process, the process can be applied to a highly integrated device to deposit an additional layer with a plurality of elements without damaging other elements previously deposited using conventional deposition. BRIEF DESCRIPTION OF THE FIGURES [0012] In order that the manner in which the above-recited and other advantages and features of the invention are obtained, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof, which are illustrated, in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: [0013] FIG. 1 shows one embodiment of an apparatus for fabricating semiconductor. [0014] FIG. 2 is an exemplary electron distribution chart. [0015] FIG. 3 shows one embodiment of an FTS unit. [0016] FIG. 4A shows one embodiment of a second apparatus for fabricating semiconductor. [0017] FIG. 4B shows one embodiment of a second apparatus for fabricating semiconductor. [0018] FIG. 5 shows a TEM image of a cross sectional view of an exemplary device fabricated with the system of FIG. 1. [0019] FIG. 6 is an enlarged view of one portion of the TEM image of FIG. 5. [0020] FIG. 7 shows an exemplary memory circuit. [0021] FIG. 8 shows another process for forming a semiconductor device. Continue reading... Full patent description for Back-biased face target sputtering based memory with low oxygen flow rate Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Back-biased face target sputtering based memory with low oxygen flow rate 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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