News Column

Patent Issued for Method of Controlling Semiconductor Process Distribution

August 27, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Lee, Ho-ki (Anyang-si, KR); Baek, Kye-hyun (Suwon-si, KR); Lee, Young-cheul (Suwon-si, KR); Min, Gyung-jin (Seongnam-si, KR), filed on September 23, 2011, was published online on August 12, 2014.

The patent's assignee for patent number 8805567 is Samsung Electronics Co., Ltd. (Suwon-Si, Gyeonggi-Do, KR).

News editors obtained the following quote from the background information supplied by the inventors: "Exemplary embodiments of the inventive concept relate to a semiconductor process, and more particularly, to a method of controlling semiconductor process distribution.

"A semiconductor process may be classified as a deposition process, an ion implantation process, a photolithography process, or an etching process. A semiconductor device is manufactured by performing the above-described semiconductor processes on a single semiconductor wafer multiple times.

"The process capability of a semiconductor wafer processing apparatus may vary due to various factors. When the process capability of the semiconductor wafer processing apparatus changes, poor or inconsistent process distribution may occur. As process distribution changes, the distribution of a process result value that is used to monitor a semiconductor process also changes, which may result in inconsistencies during the semiconductor process."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "Exemplary embodiments of the inventive concept provide a method of controlling semiconductor process distribution that is used to control process distribution with respect to a semiconductor process according to a semiconductor wafer processing apparatus.

"According to an exemplary embodiment of the inventive concept, a method of controlling semiconductor process distribution includes obtaining process distribution regarding a semiconductor process, obtaining a parameter related to the process distribution, deriving a virtual metrology model regarding process distribution of the semiconductor process by statistically analyzing the process distribution and the parameter, and correcting the process distribution by modifying a process variable related to the process distribution according to the virtual metrology model.

"The semiconductor process may be an etching process for etching a material layer formed on the semiconductor wafer to form a material layer pattern.

"Process distribution may be obtained from at least one selected from the group consisting of a critical dimension difference between the material layer patterns of a central area and a corner area of the semiconductor wafer, a range of the critical dimension difference between the material layer patterns of the central area and the corner area of the semiconductor wafer, standard deviation of the critical dimension difference between the material layer patterns of the central area and the corner area of the semiconductor wafer, and a thickness difference between the material layer patterns of the central area and the corner area of the semiconductor wafer.

"The parameter may be obtained by sensors of the semiconductor wafer processing apparatus for performing a semiconductor process.

"The sensor may be at least one selected from the group consisting of a photosensor that may monitor a polluted state of a chamber or a plasma in the semiconductor wafer processing apparatus, a temperature sensor for detecting a temperature of the chamber, and a gas analyzing sensor for analyzing reactive gas generated by the chamber.

"The parameter may be obtained from an apparatus variable value that is set in the process controller of the semiconductor wafer processing apparatus for performing a semiconductor process. An apparatus variable value that is set in the process controller may be at least one selected from the group consisting of an amount of gas supplied to the chamber of the semiconductor wafer processing apparatus, gas rates of a plurality of gases supplied to the chamber, an RF power value applied to a susceptor included in the chamber, a temperature of each part of the chamber, and a pressure of the chamber.

"A process variable, which is a variable affecting the process distribution of the semiconductor process, may be at least one selected from the group consisting of an amount of gas supplied to the chamber of the semiconductor wafer processing apparatus, gas rates of a plurality of gases supplied to the chamber, an RF power value applied to the susceptor included in the chamber, a temperature of each part of the chamber, and a pressure of the chamber.

"A statistical analysis method may be performed by using a partial least squares (PLS) method. After the process distribution is corrected, process distribution of each semiconductor wafer regarding the semiconductor process is measured, it is determined whether the process distribution of each semiconductor wafer is satisfactory, and the virtual metrology model is modified when the process distribution of each semiconductor wafer is not satisfactory.

"According to an exemplary embodiment of the inventive concept, a method of controlling semiconductor process distribution includes obtaining process distribution regarding a semiconductor process, obtaining a parameter related to the process distribution, deriving a virtual metrology model regarding process distribution of the semiconductor process by statistically analyzing the process distribution and the parameter, selecting an optimized process variable related to the process distribution, predicting process distribution of each semiconductor wafer by using the virtual metrology model, and correcting the process distribution by modifying the process variable related to the process distribution according to the predicted process distribution.

"The parameter may be obtained from at least one selected from the group consisting of values obtained from a plurality of sensors of a semiconductor wafer processing apparatus for performing the semiconductor process and an apparatus variable value set in a process controller of the semiconductor wafer processing apparatus.

"An optimized process variable may be selected using a virtual metrology model.

"After the process distribution is corrected, process distribution of each semiconductor wafer regarding the semiconductor process is measured, it is determined whether the process distribution of each semiconductor wafer is satisfactory, and the virtual metrology model is modified when the process distribution of each semiconductor wafer is not satisfactory.

"According to an exemplary embodiment of the inventive concept, a method of controlling semiconductor process distribution includes obtaining process distribution according to an etching process of a semiconductor wafer, obtaining a parameter from a semiconductor wafer etching apparatus in connection with the process distribution, deriving a virtual metrology model regarding the process distribution of the etching process of the semiconductor wafer by statistically analyzing the process distribution and the parameter, and correcting the process distribution by modifying a process variable related to the process distribution according to the virtual metrology model.

"The parameter may be obtained from at least one selected from the group consisting of values obtained from a plurality of sensors of the semiconductor wafer etching apparatus and an apparatus variable value set in a process controller of the semiconductor wafer processing apparatus.

"The sensor may be at least one selected from the group consisting of a photosensor that may monitor a polluted state of a chamber or a plasma in the semiconductor wafer etching apparatus, a temperature sensor for detecting a temperature of the chamber, and a gas analyzing sensor for analyzing reactive gas generated from the chamber.

"The apparatus variable value set in a process controller may be at least one selected from the group consisting of an amount of gas supplied to the chamber of the semiconductor wafer processing apparatus, gas rates of a plurality of gases supplied to the chamber, an RF power value applied to the susceptor included in the chamber, a temperature of each part of the chamber, and a pressure of the chamber.

"The etching process is performed to form a material layer pattern by etching a material layer formed on the semiconductor wafer, and the process distribution may be obtained from at least one selected from the group consisting of the critical dimension difference between material layer patterns of a central area and a corner area of the semiconductor wafer, a range of the critical dimension difference between the material layer patterns of the central area and the corner area of the semiconductor wafer, standard deviation of the critical dimension difference between the material layer patterns of the central area and the corner area of the semiconductor wafer, and a thickness difference between the material layer patterns of the central area and the corner area of the semiconductor wafer.

"A process variable, which is a variable affecting the process distribution of the semiconductor process, may be at least one selected from the group consisting of an amount of gas supplied to the chamber of the semiconductor wafer etching apparatus, gas rates of a plurality of gases supplied to the chamber, an RF power value applied to the susceptor included in the chamber, a temperature of each part of the chamber, and a pressure of the chamber.

"A statistical analysis method may be performed by using a partial least squares (PLS) method.

"After the process distribution is corrected, process distribution of each semiconductor wafer regarding the semiconductor etching process is measured, it is determined whether the process distribution of each semiconductor wafer is satisfactory, and the virtual metrology model is modified when the process distribution of each semiconductor wafer is not satisfactory.

"According to an exemplary embodiment of the inventive concept, a method of controlling process distribution of a semiconductor process includes receiving process distribution data representing the process distribution of the semiconductor process, receiving a parameter related to the process distribution, generating a virtual metrology model corresponding to the process distribution based on a relationship between the process distribution data and the parameter, and modifying a process variable affecting the process distribution based on the virtual metrology model.

"According to an exemplary embodiment of the inventive concept, a method of controlling process distribution of an etching process includes receiving process distribution data representing the process distribution of the etching process, wherein the etching process is performed on a semiconductor wafer by a semiconductor wafer etching apparatus, receiving a parameter related to the process distribution from the semiconductor wafer etching apparatus, generating a virtual metrology model corresponding to the process distribution of the etching process based on a relationship between the process distribution data and the parameter, and modifying a process variable affecting the process distribution based on the virtual metrology model.

"According to an exemplary embodiment of the inventive concept, a system for controlling process distribution of a semiconductor process includes a semiconductor wafer processing apparatus configured to perform the semiconductor process, and a semiconductor process controlling apparatus comprising an input circuit configured to receive process distribution data representing the process distribution of the semiconductor process and a parameter related to the process distribution, and a processor configured to generate a virtual metrology model corresponding to the process distribution based on a relationship between the process distribution data and the parameter, and modify a process variable affecting the process distribution based on the virtual metrology model."

For additional information on this patent, see: Lee, Ho-ki; Baek, Kye-hyun; Lee, Young-cheul; Min, Gyung-jin. Method of Controlling Semiconductor Process Distribution. U.S. Patent Number 8805567, filed September 23, 2011, and published online on August 12, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8805567.PN.&OS=PN/8805567RS=PN/8805567

Keywords for this news article include: Semiconductor, Samsung Electronics Co. Ltd..

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Source: Electronics Newsweekly


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