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  Automated throughput control system and method of operating the sameUSPTO Application #: 20060195212Title: Automated throughput control system and method of operating the same Abstract: An automated throughput control system and method is provided. By gathering tool specific information of a plurality of process tools on entity level, appropriate throughput related performance characteristics may be calculated with high statistical significance during moderately short time intervals. Moreover, the performance characteristics obtained from tool information may be compared to reference data, for instance provided by dynamic simulation calculations, to identify high, as well as low, performing equipment on the basis of standard process control mechanisms. (end of abstract) Agent: Williams, Morgan & Amerson - Houston, TX, US Inventors: Gunnar Flach, Thomas Quarg USPTO Applicaton #: 20060195212 - Class: 700108000 (USPTO) Related Patent Categories: Data Processing: Generic Control Systems Or Specific Applications, Specific Application, Apparatus Or Process, Product Assembly Or Manufacturing, Performance Monitoring The Patent Description & Claims data below is from USPTO Patent Application 20060195212. Brief Patent Description - Full Patent Description - Patent Application Claims
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] Generally, the present invention relates to the field of fabricating integrated circuits, and, more particularly, to the monitoring of process tool throughput of a plurality of process tools required for processing different products with different process recipes. [0003] 2. Description of the Related Art [0004] Today's global market forces manufacturers of mass products to offer high quality products at a low price. It is thus important to improve yield and process efficiency to minimize production costs. This holds especially true in the field of semiconductor fabrication, since here it is essential to combine cutting edge technology with mass production techniques. It is, therefore, the goal of semiconductor manufacturers to reduce the consumption of raw materials and consumables while at the same time improving process tool utilization. The latter aspect is especially important, since modern semiconductor facilities equipment is required, which is extremely cost-intensive and represents the dominant part of the total production costs. [0005] Integrated circuits are typically manufactured in automated or semi-automated facilities, thereby passing through a large number of process and metrology steps to complete the device. The number and the type of process steps and metrology steps a semiconductor device has to go through depends on the specifics of the semiconductor device to be fabricated. A usual process flow for an integrated circuit may include a plurality of photolithography steps to image a circuit pattern for a specific device layer into a resist layer, which is subsequently patterned to form a resist mask for further processes in structuring the device layer under consideration by, for example, etch or implant processes and the like. Thus, layer after layer, a plurality of process steps are performed based on a specific lithographic mask set for the various layers of the specified device. For instance, a sophisticated CPU requires several hundred process steps, each of which has to be carried out within specified process margins to fulfill the specifications for the device under consideration. Since many of these processes are very critical, a plurality of metrology steps have to be performed to efficiently control the process flow. Typical metrology processes may include the measurement of layer thickness, the determination of dimensions of critical features, such as the gate length of transistors, the measurement of dopant profiles, and the like. As the majority of the process margins are device specific, many of the metrology processes and the actual manufacturing processes are specifically designed for the device under consideration and require specific parameter settings at the adequate metrology and process tools. [0006] In a semiconductor facility, usually a plurality of different product types are manufactured at the same time, such as memory chips of different design and storage capacity, CPUs of different design and operating speed, and the like, wherein the number of different product types may even reach a hundred and more in production lines for manufacturing ASICs (application specific ICs). Since each of the different product types may require a specific process flow, different mask sets for the lithography, specific settings in the various process tools, such as deposition tools, etch tools, implantation tools, CMP (chemical mechanical polishing) tools, and the like, may be necessary. Consequently, a plurality of different tool parameter settings and product types may be encountered simultaneously in a manufacturing environment. [0007] Hereinafter, the parameter setting for a specific process in a specified process tool or metrology or inspection tool may commonly be referred to as a process recipe or simply as a recipe. Thus, a large number of different process recipes, even for the same type of process tools, may be required which have to be applied to the process tools at the time the corresponding product types are to be processed in the respective tools. However, the sequence of process recipes performed in process and metrology tools or in functionally combined equipment groups, as well as the recipes themselves, may have to be frequently altered due to fast product changes and highly variable processes involved. As a consequence, the tool performance, especially in terms of throughput, is a very critical manufacturing parameter as it significantly affects the overall production costs of the individual devices. The progression of throughput over time of individual process and metrology tools, or even certain entities thereof, such as process modules, substrate robot handlers, load ports and the like, may, however, remain unobserved due to the complexity of the manufacturing sequences including a large number of product types and a corresponding large number of processes, which in turn are subjected to frequent recipe changes. Hence, low-performing tools may remain undetected for a long time, when the performance of an equipment group which the tool under consideration belongs to is within its usual performance margin that typically has to be selected to allow a relatively wide span of variations, owing to the complexity of the processes and the tools involved. [0008] Ideally, the effect of each individual process on each substrate would be detected by measurement and the substrate under consideration would be released for further process only if the required specifications were met. A corresponding process control in view of the result of each individual process, however, is not practical, since measuring the effects of certain processes may require relatively long measurement times or may even necessitate the destruction of the sample. Moreover, immense effort in terms of time and equipment would have to be made on the metrology side to provide the required measurement results. Additionally, utilization of the process tools involved would be minimized, since the tool would be released only after the provision of the measurement result and its assessment. [0009] Typically, due to the lack of "knowledge" regarding the effect of the individual processes owing to the restricted metrology capability, statistical methods, such as mean values and corresponding standard deviations and the like, have been introduced for adjusting process parameters to significantly relax the above problem and to allow a moderately high utilization of the process tools, while at the same time attaining a relatively high product yield. Moreover, a process control strategy has been introduced and is continuously improved which allows a high degree of process control, desirably on a run-to-run basis, without the necessity of an immediate response of a measurement tool. In this control strategy, the so-called advanced process control, a model of a process or of a group of interrelated processes, is established and implemented in an appropriately configured process controller. Based on a certain amount of measurement results of preceding and/or subsequent processes, a feed forward and/or feedback control loop is established to maintain the process variability within predefined tolerances. Although well-established statistical process control (SPC) mechanisms, in combination with advanced process control (APC) strategies, provide the potential for achieving a high degree of quality of the products on the basis of a restricted amount of process information, these strategies may not sufficiently take into consideration other performance criteria of a process line, such as the throughput of the process tools involved. For instance, the malfunction of an entity of a process tool, such as a process module, a substrate handler robot, a load port and the like, may not necessarily severely compromise the quality of the substrates processed, but may in a more or less subtle manner influence the overall throughput of the process tool or a group of process tools. Similarly, process changes and/or setup changes of one or more process tools, which may be performed to take into account process variations and/or to improve results of individual processes, may even promote an enhanced quality of the result of the process or processes under consideration, but may result in a reduced throughput owing to, for instance, increased robot activities, additional recipe steps and the like. Hence, monitoring of the performance of equipment and equipment groups with respect to throughput efficiency is highly complex, and even throughput studies at entity level, i.e., monitoring some or all of the individual entities comprising a specified process tool, such as process modules, robot handlers, load ports and the like, may represent a less attractive solution, since resources in operations and industrial engineering are limited and an immediate response to the throughput changes may not be practical, even though the throughput studies may reveal certain details regarding one or more specified process tools. [0010] In view of the situation described above, there is therefore a need for an enhanced technique that enables enhancement of the efficiency of a semiconductor production process, especially in view of throughput related issues. SUMMARY OF THE INVENTION [0011] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later. [0012] Generally, the present invention is directed to an automated throughput control (ATC) system to provide the potential for monitoring throughput related parameters in an automated fashion, thereby enabling substantially continuous data collection for the assessment of the throughput efficiency with high statistical significance, since a great amount of process data may be gathered and processed. Consequently, even subtle throughput related performance variations may be automatically detected and may be compensated for or otherwise used for further control tasks. Thus, in illustrative embodiments, a throughput related performance characteristic is determined for a plurality of process tools, wherein the throughput related performance characteristic is defined as a quantitative measure of the throughput performance of a process tool in relation to a specified reference performance of the process tool under consideration of the operating conditions of the process tool. [0013] According to one illustrative embodiment of the present invention, a system comprises an interface configured to receive process messages from a plurality of process tools. Furthermore, a throughput control unit is provided, which is connected to the interface and which is configured to automatically determine a throughput related performance characteristic for each of the plurality of process tools. [0014] In accordance with yet another illustrative embodiment of the present invention, a method comprises receiving process messages from a plurality of process tools used in a manufacturing process line by a throughput control unit and determining a throughput related performance characteristic for each of the plurality of process tools on the basis of the process messages. In illustrative embodiments, the method may further comprise performing control tasks related to the plurality of process tools on the basis of the performance characteristic. BRIEF DESCRIPTION OF THE DRAWINGS [0015] The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which: [0016] FIG. 1a schematically depicts a system for monitoring and/or controlling the throughput of a plurality of process tools in an automated fashion in accordance with illustrative embodiments of the present invention; and [0017] FIG. 1b schematically shows an automated throughput controller (ATC) in accordance with further illustrative embodiments of the present invention in more detail. [0018] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION [0019] Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure. [0020] The present invention will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present invention with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present invention. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase. Continue reading... Full patent description for Automated throughput control system and method of operating the same Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Automated throughput control system and method of operating the same patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. 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