Patent Publication Number: US-2022235450-A1

Title: Sputtering apparatus and method for fabricating semiconductor device using the same

Description:
This application is a continuation of U.S. application Ser. No. 16/793,096, filed on Feb. 18, 2020, which claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0082699, filed on Jul. 9, 2019, in the Korean Intellectual Property Office (KIPO), the disclosure of each of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to a sputtering apparatus and a method for fabricating a semiconductor device using the same. 
     2. Description of the Related Art 
     According to the speeding-up and/or low power consumption requirements for electronic devices, demands for speeding-up and/or low power operation of semiconductor memory elements included in electronic devices are increasing. To satisfy such demands, magnetic memory elements have been suggested as semiconductor memory elements. The magnetic memory elements are good candidates as next-generation semiconductor memory elements due to the high-speed and/or non-volatile characteristics of such devices. 
     The magnetic memory element may include a magnetic tunnel junction pattern (MTJ). The magnetic tunnel junction pattern may include two magnetic substances and an insulation film disposed therebetween. 
     SUMMARY 
     Some example embodiments of the present disclosure provide a sputtering apparatus which enhances efficiency of processes by performing a sputtering process by using a plurality of radio frequency (RF) sources having different frequencies, respectively, and by performing a cleaning process with respect to a target (or alternatively, referred to a sputtering target). 
     Some example embodiments of the present disclosure provide a sputtering apparatus which reduces occurrence of a process defect by providing a gas inlet at an upper portion of a chamber to allow a source gas to flow therethrough, and thereby preventing particles attached to a chamber shield from being dispersed. 
     Some example embodiments of the present disclosure provide a method for fabricating a semiconductor device using a sputtering apparatus which enhances efficiency of processes by performing a sputtering process by using a plurality of RF sources having different frequencies, respectively, and by performing a cleaning process with respect to a target. 
     According to an example embodiment of the present disclosure, a sputtering apparatus may include a chamber, a stage inside the chamber, the stage configured to receive a substrate thereon, a first sputter gun configured to provide a sputtering source to an inside of the chamber, a first RF source configured to provide a first power to the first sputter gun, the first power having a first frequency, and a second RF source configured to provide a second power to the first sputter gun, the second power having a second frequency lower than the first frequency. 
     According to an example embodiment of the present disclosure, a sputtering apparatus may include a chamber, a stage inside the chamber, the stage configured to receive a substrate thereon, a first sputter gun configured to provide a sputtering source to an inside of the chamber, a first RF source configured to provide a first power to the first sputter gun, the first power having a first frequency, a chamber shield at both sides of the stage, the chamber shield extending from an area under the stage to be inclined toward a sidewall of the chamber, and a gas inlet on an upper surface of the chamber shield, the gas inlet configured to flow a source gas into the chamber. 
     According to an example embodiment of the present disclosure, a sputtering apparatus may include a chamber, a stage inside the chamber, the stage configured to receive a substrate thereon, a first sputter gun and a second sputter gun configured to provide a sputtering source to an inside of the chamber, a first sputter gun and a second sputter gun spaced apart from each other, a first RF source configured to provide a first power having to the first sputter gun, the first power having a first frequency, a second RF source configured to provide a second power to the first sputter gun, the second power having a second frequency lower than the first frequency, a third RF source configured to provide a third power to the second sputter gun, the third power having the first frequency, a fourth RF source configured to provide a fourth power to the second sputter gun, the fourth power having the second frequency, a chamber shield at both sides of the stage, the chamber shield extending from an area under the stage to be inclined toward a sidewall of the chamber, and a gas inlet at an upper surface of the chamber shield, the gas inlet configured to flow a source gas into the chamber. 
     According to an example embodiment of the present disclosure, a method for fabricating a semiconductor device may include forming a first magnetic film on a substrate, loading the substrate having the first magnetic film thereon into a chamber, providing a first power having a first frequency to a first sputter gun, providing a first sputtering source generated from the first sputter gun to an inside of the chamber, depositing an insulation film on the first magnetic film by using the first sputtering source, unloading the substrate from the chamber, providing a second power having a second frequency to the first sputter gun, the second frequency being higher than the first frequency, and cleaning a lower surface of a target exposed at a lower portion of the first sputter gun by using the second power. 
     The present inventive concepts are not limited to the example embodiments mentioned above, and other example embodiments of the present inventive concepts may be clearly understood to those skilled in the art based on the description provided below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present disclosure will become more apparent to those of ordinary skill in the art by describing in detail some example embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1  is a top view of a sputtering apparatus according to some example embodiments of the present disclosure; 
         FIG. 2  is a cross-sectional view taken along line A-A′ of  FIG. 1 ; 
         FIGS. 3 to 5  are views provided to explain a surface of a target installed on a sputter gun of a sputtering apparatus according to some example embodiments of the present disclosure; 
         FIG. 6  is a cross-sectional view of a sputtering apparatus according to some other example embodiments of the present disclosure; 
         FIG. 7  is a cross-sectional view of a sputtering apparatus according to some other example embodiments of the present disclosure; 
         FIG. 8  is a cross-sectional view of a sputtering apparatus according to some other example embodiments of the present disclosure; 
         FIG. 9  is a cross-sectional view of a sputtering apparatus according to some other example embodiments of the present disclosure; 
         FIG. 10  is a flowchart provided to explain a method for fabricating a semiconductor device using a sputtering apparatus according to some example embodiments of the present disclosure; 
         FIGS. 11 to 14  are views illustrating intermediate stages of fabrication, provided to explain a method for fabricating a semiconductor device using a sputtering apparatus according to some example embodiments of the present disclosure; 
         FIG. 15  is a view provided to explain a semiconductor device fabricated by a method for fabricating a semiconductor device according to some example embodiments of the present disclosure; and 
         FIG. 16  is a view provided to explain a semiconductor device fabricated by a method for fabricating a semiconductor device according to some other example embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     While the term “same” or “identical” is used in description of example embodiments, it should be understood that some imprecisions may exist. Thus, when one element is referred to as being the same as another element, it should be understood that an element or a value is the same as another element within a desired manufacturing or operational tolerance range (e.g., ±10%). 
     When the terms “about” or “substantially” are used in this specification in connection with a numerical value, it is intended that the associated numerical value includes a manufacturing or operational tolerance (e.g., ±10%) around the stated numerical value. Moreover, when the words “generally” and “substantially” are used in connection with geometric shapes, it is intended that precision of the geometric shape is not required but that latitude for the shape is within the scope of the disclosure. 
     Hereinbelow, a sputtering apparatus according to some example embodiments of the present disclosure will be described with reference to  FIGS. 1 and 5 . 
       FIG. 1  is a top view of a sputtering apparatus according to some example embodiments of the present disclosure.  FIG. 2  is a cross-sectional view taken along line A-A′ of  FIG. 1 . FIGS.  3  to  5  are views provided to explain a surface of a target installed on a sputter gun of the sputtering apparatus according to some example embodiments of the present disclosure. 
     Referring to  FIGS. 1 to 5 , the sputtering apparatus according to some example embodiments of the present disclosure includes a chamber  100 , a stage  101 , first to fourth sputter guns  110 ,  120 ,  130 ,  140 , first to fourth radio frequency (RF) sources  151 ,  152 ,  153 ,  154 , a chamber shield  160 , and a gas inlet  170 . 
     A sputtering process may be performed inside the chamber  100 . The sputtering process may be a sputtering deposition process for depositing a thin film. The chamber  100  may be a vacuum chamber. 
     The stage  101  may be disposed inside the chamber  100 . A substrate  10  loaded into the chamber  100  may be positioned on the stage  101 . The stage  101  may be connected to a support  102  extended to the outside of the chamber  100 . The support  102  may rotate the stage  101 . 
     The support  102  may rotate the stage  101  while the sputtering process is being performed in the chamber  100 . Accordingly, the substrate  10  may be rotated while the sputtering process is being performed. 
     A plurality of sputter guns may be disposed in the chamber  100 . For example, the first to fourth sputter guns  110 ,  120 ,  130 ,  140  may be disposed in the chamber  100 . Although it is illustrated that the four sputter guns are disposed in the chamber  100 , this is only for convenience of explanation, and the present disclosure is not limited thereto. That is, in some other example embodiments, the number of sputter guns disposed in the chamber  100  may vary. 
     Each of the first to fourth sputter guns  110 ,  120 ,  130 ,  140  may be disposed on an upper surface of the chamber  100 . Each of the first to fourth sputter guns  110 ,  120 ,  130 ,  140  may be spaced apart from one another when viewed in a plan view, as shown in  FIG. 1 . For example, the first sputter gun  110  and the second sputter gun  120  may be disposed to be symmetric with reference to the stage  101 . In addition, the third sputter gun  130  and the fourth sputter gun  140  may be disposed to be symmetric with reference to the stage  101 . However, the present disclosure is not limited thereto. 
     Each of the first to fourth sputter guns  110 ,  120 ,  130 ,  140  may be spaced apart from the substrate  10  in a vertical direction. In addition, each of the first to fourth sputter guns  110 ,  120 ,  130 ,  140  may be spaced apart from the substrate  10  in a horizontal direction. 
     Each of the first to fourth sputter guns  110 ,  120 ,  130 ,  140  may provide a sputtering source to the inside of the chamber  100 . 
     The first sputter gun  110  may include a first target  111 , a first target shield  112 , and a first plate  113 . 
     The first target  111  may be disposed at a lower portion (or alternatively, a bottom portion) of the first sputter gun  110 . That is, a lower surface  111   a  of the first target  111  may be exposed by the first target shield  112  at the lower portion of the first sputter gun  110 . 
     The lower surface  111   a  of the first target  111  may be parallel to an upper surface of the stage  101 . However, the present disclosure is not limited thereto. That is, in some other example embodiments, the lower surface  111   a  of the first target  111  may be disposed to be inclined with respect to the upper surface of the stage  101 . 
     The first target  111  may include a metallic oxide, for example, at least one of a magnesium (Mg) oxide, a titanium (Ti) oxide, an aluminum (Al) oxide, a calcium (Ca) oxide, a zirconium (Zr) oxide, a magnesium-zinc (Mg—Zn) oxide, or a magnesium-boron (Mg—B) oxide. However, the present disclosure is not limited thereto. 
     The first target shield  112  may surround a sidewall of the first target  111 . The first target shield  112  may protrude toward a lower surface of the chamber  100  further than the lower surface  111   a  of the first target  111 . 
     The first plate  113  may be connected with the first target  111  and the first target shield  112 . The first plate  113  may fix the first target  111  and the first target shield  112  to the chamber  100 . 
     The first plate  113  may provide a power to the first target  111  by using first and second RF sources  151 ,  152  disposed therein. 
     The second sputter gun  120  may be spaced apart from the first sputter gun  110 . The second sputter gun  120  may include a second target  121 , a second target shield  122 , and a second plate  123 . 
     The second target  121  may be disposed at a lower portion (or alternatively, a bottom portion) of the second sputter gun  120 . That is, a lower surface  121   a  of the second target  121  may be exposed by the second target shield  122  at the lower portion of the second sputter gun  120 . 
     The lower surface  121   a  of the second target  121  may be parallel to the upper surface of the stage  101 . However, the present disclosure is not limited thereto. That is, in some other example embodiments, the lower surface  121   a  of the second target  121  may be disposed to be inclined with respect to the upper surface of the stage  101 . 
     The second target  121  may include a metallic oxide, for example, at least one of a magnesium (Mg) oxide, a titanium (Ti) oxide, an aluminum (Al) oxide, a calcium (Ca) oxide, a zirconium (Zr) oxide, a magnesium-zinc (Mg—Zn) oxide, or a magnesium-boron (Mg—B) oxide. However, the present disclosure is not limited thereto. 
     The second target shield  122  may surround a sidewall of the second target  121 . The second target shield  122  may protrude toward the lower surface of the chamber  100  further than the lower surface  121   a  of the second target  121 . 
     The second plate  123  may be connected with the second target  121  and the second target shield  122 . The second plate  123  may fix the second target  121  and the second target shield  122  to the chamber  100 . 
     The second plate  123  may provide a power to the second target  121  by using third and fourth RF sources  153 ,  154  disposed therein. 
     The third sputter gun  130  and the fourth sputter gun  140  may have the same structure as the first sputter gun  110 . 
     That is, the third sputter gun  130  may include a third target  131  disposed at a lower portion (or alternatively, a bottom portion) of the third sputter gun  130 , a third target shield (not shown) surrounding a sidewall of the third target  131 , and a third plate  133  including RF sources. 
     Further, the fourth sputter gun  140  may include a fourth target  141  disposed at a lower portion (or alternatively, a bottom portion) of the fourth sputter gun  140 , a fourth target shield (not shown) surrounding a sidewall of the fourth target  141 , and a fourth plate  143  including RF sources. 
     The first to fourth targets  111 ,  121 ,  131 ,  141  may include, for example, the same material with one another. However, the present disclosure is not limited thereto. That is, in some other example embodiments, at least one of the first to fourth targets  111 ,  121 ,  131 ,  141  may include a different material. 
     The first RF source  151  and the second RF source  152  may be disposed inside the first plate  113 . Although  FIG. 2  depicts that each of the first RF source  151  and the second RF source  152  is in contact with the first target  111 , the present disclosure is not limited thereto. That is, in some other example embodiments, each of the first RF source  151  and the second RF source  152  may be spaced apart from the first target  111 . 
     The first RF source  151  may provide a first power having a first frequency to the first sputter gun  110 . That is, the first RF source  151  may provide the first power having the first frequency to the first target  111 . 
     The second RF source  152  may provide a second power having a second frequency to the first sputter gun  110 . That is, the second RF source  152  may provide the second power having the second frequency to the first target  111 . 
     The third RF source  153  and the fourth RF source  154  may be disposed inside the second plate  123 . Although  FIG. 2  depicts that each of the third RF source  153  and the fourth RF source  154  is in contact with the second target  121 , the present disclosure is not limited thereto. That is, in some other example embodiments, each of the third RF source  153  and the fourth RF source  154  may be spaced apart from the second target  121 . 
     The third RF source  153  may provide a third power having the first frequency to the second sputter gun  120 . That is, the third RF source  153  may provide the third power having the first frequency to the second target  121 . 
     The fourth RF source  154  may provide a fourth power having the second frequency to the second sputter gun  120 . That is, the fourth RF source  154  may provide the fourth power having the second frequency to the second target  121 . 
     Each of the first frequency and the second frequency may be, for example, between about 13.56 MHz and about 40.68 MHz. 
     The first frequency may be higher than the second frequency. For example, the first frequency may be about 40.68 MHz and the second frequency may be about 13.56 MHz. That is, the first RF source  151  may provide the first power having a high frequency to the first target  111 , and the third RF source  153  may provide the third power having a high frequency to the second target  121 . Further, the second RF source  152  may provide the second power having a low frequency to the first target  111 , and the fourth RF source  154  may provide the fourth power having a low frequency to the second target  121 . 
     Each of the third plate  133  and the fourth plate  134  may have RF sources corresponding to the first RF source  151  and the second RF source  152  disposed therein. 
     The first sputter gun  110  may have a first projection area PA 1 . The first projection area PA 1  may be an area extended from the lower surface  111   a  of the first target  111  in the vertical direction. The first projection area PA 1  may be spaced apart from the substrate  10  in the horizontal direction. That is, the first projection area PA 1  may not to overlap the substrate  10  in the vertical direction. Sputtering sources generated from the lower surface  111   a  of the first target  111  may be distributed inside the first projection area PAL 
     The second sputter gun  120  may have a second projection area PA 2 . The second projection area PA 2  may be an area extended from the lower surface  121   a  of the second target  121  in the vertical direction. The second projection area PA 2  may be spaced apart from the substrate  10  in the horizontal direction. That is, the second projection area PA 2  may not overlap the substrate  10  in the vertical direction. Sputtering sources generated from the lower surface  121   a  of the second target  121  may be distributed inside the second projection area PA 2 . 
     Each of the third sputter gun  130  and the fourth sputter gun  140  may have the same or substantially similar projection area as the first projection area PAL 
     The chamber shield  160  may be disposed at both sides of the stage  101 . The chamber shield  160  may be disposed, for example, to surround a side surface of the stage  101 . The chamber shield  160  may be extended from a lower portion (or alternatively, a bottom portion) of the stage  101  to be inclined toward a sidewall and an upper surface of the chamber  100 . The chamber shield  160  may be in contact with the sidewall of the chamber  100 . 
     The chamber shield  160  may be spaced apart from a side surface of the stage  101 . That is, a space may be formed between the chamber shield  160  and the stage  101  to allow a gas to pass therethrough. However, the present disclosure is not limited thereto. 
     The gas inlet  170  may be disposed at an upper surface  160   a  of the chamber shield  160 . For example, the gas inlet  170  may penetrate through the upper surface of the chamber  100  as shown in  FIG. 2 . However, the present disclosure is not limited thereto. That is, in some other example embodiments, the gas inlet  170  may be disposed at the upper surface  160   a  of the chamber shield  160  to penetrate through the sidewall of the chamber  100 . 
     A source gas may be drawn into the chamber  100  through the gas inlet  170 . The source gas may be, for example, an argon (Ar) gas, although the present disclosure is not limited thereto. 
     When a sputtering process is performed inside the chamber  100 , each of the first to fourth targets  111 ,  121 ,  131 ,  141  may be sputtered by plasma which is generated by using the source gas provided to the inside of the chamber  100 . Some of the sputtering sources sputtered from each of the first to fourth targets  111 ,  121 ,  131 ,  141  may be deposited on the substrate  10 , thereby forming a thin film on the substrate  10 . 
       FIGS. 3 to 5  illustrate the lower surface  111   a  of the first target  111  which is sputtered. 
     Referring to  FIGS. 2 and 3 , when the second power having the second frequency (e.g., about 13.56 MHz) is provided to the first target  111  from the second RF source  152 , a first target erosion area E 1  may be formed on the lower surface  111   a  of the first target  111 . 
     The first target erosion area E 1  may have a first width W 1  and may be recessed toward an inside of the first target  111  to have a sharp end portion. This is because ion energy is high at a low frequency, and sputtering occurs in a relatively narrow area. 
     Referring to  FIGS. 2 and 5 , when the first power having the first frequency (e.g., about 40.68 MHz) is provided to the first target  111  from the first RF source  151 , a third target erosion area E 3  may be formed on the lower surface  111   a  of the first target  111 . 
     The third target erosion area E 3  may have a third width W 3  larger than the first width W 1  of the first target erosion area E 1 , and may be recessed to be concave toward an inside of the first target  111 . This is because ion energy is low at a high frequency and sputtering occurs in a relatively wide area. 
     In the case in which a width of a target erosion area is narrow, the probability that micro arching occurs increases when particles of the source gas (e.g., particles of the argon (Ar) gas) enter the target erosion area formed at the lower surface  111   a  of the first target  111 . Accordingly, peroxidized oxide particles may be generated in a portion where micro arching occurs. 
     The sputtering apparatus according to some example embodiments of the present disclosure may deposit a thin film (e.g., an insulation film) on the substrate  10  by using the second RF source  152 , and may clean the lower surface  111   a  of the first target  111  by using the first RF source  151 . 
     For example, the sputtering process may be performed by providing the second power having the second frequency, which is a low frequency, to the first target  111  by using the second RF source  152 , and by sputtering the lower surface  111   a  of the first target  111 . In this case, the first target erosion area E 1  having the first width W 1  may be formed on the lower surface  111   a  of the first target  111  as shown in  FIG. 3 . 
     After the sputtering process is completed, the cleaning process may be performed on the lower surface  111   a  of the first target  111  by providing the first power having the first frequency, which is a high frequency, to the first target  111  by using the first RF source  151 . In this case, the third target erosion area E 3  having the third width W 3 , which is wider than the first width W 1 , may be formed on the lower surface  111   a  of the first target  111  as shown in  FIG. 5 . Accordingly, the generation of peroxidized oxide particles by micro arching can be reduced. 
     Referring to  FIGS. 2 and 4 , when the first power having the first frequency (e.g., about 40.68 MHz) is provided to the first target  111  from the first RF source  151  for a relatively short time, a second target erosion area E 2  may be formed on the lower surface  111   a  of the first target  111 . 
     The second target erosion area E 2  may have a second width W 2 , and may be recessed to be concave toward an inside of the first target  111 . 
     The sputtering apparatus according to some other example embodiments of the present disclosure may deposit a thin film (e.g., an insulation film) on the substrate for a relatively short time by using the first RF source  151 , and may proceed with a cleaning process with respect to the lower surface  111   a  of the first target  111  for a relatively long time by using the first RF source  151 . 
     For example, the sputtering process may be performed by providing the first power having the first frequency, which is a high frequency, to the first target  111  for a relatively short time by using the first RF source  151 , and by sputtering the lower surface  111   a  of the first target  111 . In this case, the second target erosion area E 2  having the second width W 2  may be formed on the lower surface  111   a  of the first target  111  as shown in  FIG. 4 . 
     After the sputtering process is completed, the cleaning process may be performed on the lower surface  111   a  of the first target  111  by providing the first power having the first frequency, which is a high frequency, to the first target  111  for a relatively long time by using the first RF source  151 . In this case, the third target erosion area E 3  having the third width W 3 , which is wider than the second width W 2 , may be formed on the lower surface  111   a  of the first target  111  as shown in  FIG. 5 . Accordingly, the generation of peroxidized oxide particles by micro arching can be reduced. 
     The sputtering apparatus according to some example embodiments of the present disclosure can enhance efficiency of processes by performing the sputtering process and the cleaning process on the target by using the plurality of RF sources having different frequencies, respectively. 
     Further, the sputtering apparatus according to some example embodiments of the present disclosure can reduce occurrence of a process defect by providing the gas inlet at an upper portion of the chamber to allow the source gas to flow therethrough, thereby preventing particles attached to the chamber shield from being dispersed. 
     Hereinbelow, a sputtering apparatus according to some other example embodiments of the present disclosure will be described with reference to  FIG. 6 . The difference from the sputtering apparatus illustrated in  FIG. 2  will be explained. 
       FIG. 6  is a cross-sectional view of a sputtering apparatus according to some other example embodiments of the present disclosure. 
     Referring to  FIG. 6 , the sputtering apparatus according to some other example embodiments of the present disclosure may have a gas inlet  270  disposed on a lower portion (or alternatively, a bottom portion) of the chamber  100 . For example, the gas inlet  270  may be disposed between a lower surface of the chamber  100  and the chamber shield  160  to allow a source gas to flow into the chamber  100 . 
     Hereinbelow, a sputtering apparatus according to some other example embodiments of the present disclosure will be described with reference to  FIG. 7 . The difference from the sputtering apparatus illustrated in  FIG. 2  will be explained. 
       FIG. 7  is a cross-sectional view of a sputtering apparatus according to some other example embodiments of the present disclosure. 
     Referring to  FIG. 7 , the sputtering apparatus according to some other example embodiments of the present disclosure may have one first RF source  351  disposed inside the first plate  113 , which is installed in the first sputter gun  110 . Further, one third RF source  353  may be disposed inside the first plate  113 , which is installed in the second sputter gun  120 . 
     The first RF source  351  may provide the first power having the first frequency (e.g., about 40.68 MHz) which is a high frequency to the first target  111 . The third RF source  353  may provide the third power having the first frequency (e.g., about 40.68 MHz) which is a high frequency to the second target  121 . 
     Hereinbelow, a sputtering apparatus according to some other example embodiments of the present disclosure will be described with reference to  FIG. 8 . The difference from the sputtering apparatus illustrated in  FIG. 2  will be explained. 
       FIG. 8  is a cross-sectional view provided to explain a sputtering apparatus according to some other example embodiments of the present disclosure. 
     Referring to  FIG. 8 , the sputtering apparatus according to some other example embodiments of the present disclosure may have a first sputter gun  410  and a second sputter gun  420  which are disposed adjacent to each other. The first sputter gun  410  and the second sputter gun  420  may be connected to each other through a first plate  413 . 
     One first RF source  451  and one second RF source  452  may be disposed inside the first plate  413 . 
     The first RF source  451  may provide the first power having the first frequency (e.g., about 40.68 MHz) which is a high frequency to a first target  411  and a second target  421 . The second RF source  452  may provide the second power having the second frequency (e.g., about 13.56 MHz) which is a low frequency to the first target  411  and the second target  421 . 
     Each of the first sputter gun  410  and the second sputter gun  420  may overlap the stage  101  in the vertical direction. 
     A lower surface  411   a  of the first target  411  exposed by a first target shield  412  at a lower portion (or alternatively, a bottom portion) of the first sputter gun  410  may be inclined with respect to the upper surface of the stage  101 . The first target shield  412  may surround a sidewall of the first target  411 . 
     A lower surface  421   a  of the second target  421  exposed by a second target shield  422  at a lower portion (or alternatively, a bottom portion) of the second sputter gun  420  may be inclined with respect to the upper surface of the stage  101 . The second target shield  422  may surround a sidewall of the second target  421 . 
     The first sputter gun  410  may have a third projection area PA 3 . The third projection area PA 3  may be an area extending from the lower surface  411   a  of the first target  411  in the vertical direction. The third projection area PA 3  may be spaced apart from the substrate  10  in the horizontal direction. 
     The second sputter gun  420  may have a fourth projection area PA 4 . The fourth projection area PA 4  may be an area extending from the lower surface  421   a  of the second target  421  in the vertical direction. The fourth projection area PA 4  may be spaced apart from the substrate  10  in the horizontal direction. 
     Hereinbelow, a sputtering apparatus according to some other example embodiments of the present disclosure will be described with reference to  FIG. 9 . The difference from the sputtering apparatus illustrated in  FIG. 8  will be explained. 
       FIG. 9  is a cross-sectional view of a sputtering apparatus according to some other example embodiments of the present disclosure. 
     Referring to  FIG. 9 , the sputtering apparatus according to some other example embodiments of the present disclosure may have one first RF source  551  disposed inside the first plate  413  and shared by the first sputter gun  410  and the second sputter gun  420 . 
     The first RF source  551  may provide the first power having the first frequency (e.g., about 40.68 MHz) which is a high frequency to the first target  411  and the second target  421 , respectively. 
     Hereinafter, a method for fabricating a semiconductor device using a sputtering apparatus according to some example embodiments of the present disclosure will be described with reference to  FIGS. 1, 2, and 10 to 14 . 
       FIG. 10  is a flowchart provided to explain a method for fabricating a semiconductor device using a sputtering apparatus according to some example embodiments of the present disclosure.  FIGS. 11 to 14  are views illustrating intermediate stages of fabrication, provided to explain the method for fabricating the semiconductor device using the sputtering apparatus according to some example embodiments of the present disclosure. 
     Referring to  FIGS. 1, 2, 10 and 11 , a lower interlayer insulation film  20  may be formed on the substrate  10 . The substrate  10  may include a semiconductor substrate. The substrate  10  may include, for example, a silicone substrate, a germanium substrate, or a silicone-germanium substrate, or the like. In some example embodiments, selectors (not shown) may be formed on the substrate  10  and the lower interlayer insulation film  20  may cover the selectors. The selectors may be, for example, field effect transistors. In some example embodiments, the selectors may be diodes. The lower interlayer insulation film  20  may be formed as a single layer or a multi-layer including an oxide, a nitride, and/or an oxynitride. 
     Next, a lower contact plug  30  may be formed in the lower interlayer insulation film  20 . The lower contact plug  30  may penetrate through the lower interlayer insulation film  20 , and may be electrically connected to any one of the selectors. The lower contact plug  30  may include at least one of a doped semiconductor material (e.g., doped silicon), metal (e.g., tungsten, titanium, and/or tantalum), a conductive metallic nitride (e.g., a titanium nitride, a tantalum nitride, and/or a tungsten nitride), or a metal-semiconductor compound (e.g., metal silicide). 
     Next, a lower electrode film BEL may be formed on the lower interlayer insulation film  20 . The lower electrode film BEL may cover the lower contact plug  30 . The lower electrode film BEL may include a conductive metallic nitride such as a titanium nitride and/or tantalum nitride, or the like. The lower electrode film BEL may include a material (e.g., ruthenium (Ru)) facilitating crystal growth of magnetic films which will be described below. The lower electrode film BEL may be formed by performing, for example, one of sputtering deposition, chemical vapor deposition, or atomic layer deposition process. 
     Next, a first magnetic film  40  may be formed on the lower electrode film BEL (S 110 ). The first magnetic film  40  may be a pinned layer which has a magnetization direction fixed in one direction, or may be a free layer having a changeable magnetization direction. The first magnetic film  40  may include at least one ferromagnetic element (e.g., cobalt, nickel, and iron). The first magnetic film  40  may be formed by performing, for example, one of sputtering deposition, chemical vapor deposition, or physical vapor deposition process. 
     Next, the substrate  10  having the first magnetic film  40  formed thereon may be loaded onto the stage  101  disposed inside the chamber  100  (S 120 ). After the substrate  10  having the first magnetic film  40  formed thereon is loaded into the chamber  100 , a source gas (e.g., argon (Ar) gas) may be provided to the inside of the chamber  100  through the gas inlet disposed on the upper portion of the chamber  100 . 
     Referring to  FIGS. 1, 2, 10 and 12 , a sputtering process P 1  may be performed by providing the second power having the second frequency (e.g., about 13.56 MHz), which is a low frequency, to the first to fourth targets  111 ,  121 ,  131 ,  141 , and by sputtering the respective lower surfaces of the first to fourth targets  111 ,  121 ,  131 ,  141 . 
     Sputtering sources generated from the first to fourth sputter guns  110 ,  120 ,  130 ,  140  may be provided to the inside of the chamber  100 . An insulation film  50  may be formed on the first magnetic film  40  through the sputtering process P 1  (S 130 ). 
     The insulation film  50  may be a tunnel barrier film. The insulation film  50  may include the same material as those of the first to fourth targets  111 ,  121 ,  131 ,  141 . The insulation film  50  may include a metallic oxide. The insulation film  50  may include, for example, a magnesium (Mg) oxide, a titanium (Ti) oxide, an aluminum (Al) oxide, a calcium (Ca) oxide, a zirconium (Zr) oxide, a magnesium-zinc (Mg—Zn) oxide, or a magnesium-boron (Mg—B) oxide. 
     While the sputtering process P 1  is being performed, some of the sputtering sources generated from the first to fourth targets  111 ,  121 ,  131 ,  141  may be diffused toward the substrate  10  from the first projection area PA 1  and the second projection area PA 2 , and the diffused sputtering sources may be deposited on the first magnetic film  40 , thereby forming the insulation film  50 . 
     Next, the substrate  10  having the insulation film  50  deposited thereon may be unloaded from the chamber  100  (S 140 ). 
     Next, a cleaning process may be performed with respect to the respective lower surfaces of the first to fourth targets  111 ,  121 ,  131 ,  141  by providing the first power having the first frequency (e.g., about 40.68 MHz), which is a high frequency, to the first to fourth targets  111 ,  121 ,  131 ,  141  (S 150 ). 
     Referring to  FIGS. 10 and 13 , a second magnetic film  60  may be formed on the insulation film  50  of the substrate  10  which has been unloaded from the chamber  100  (S 160 ). The second magnetic film  60  may be a pinned layer which has a magnetization direction fixed in one direction, or may be a free layer having a changeable magnetization direction. Any one of the first and second magnetic films  40 ,  60  may correspond to a pinned layer having a magnetization direction fixed in one direction, and the other one of the first and second magnetic films  40 ,  60  may correspond to a free layer having a magnetization direction which is changeable in parallel or semi-parallel to the fixed magnetization direction. The second magnetic film  60  may include at least one ferromagnetic element (e.g., cobalt, nickel, and/or iron). The second magnetic film  60  may be formed by performing, for example, one of sputtering deposition, chemical vapor deposition, or physical vapor deposition process. 
     Next, an upper electrode TE may be formed on the second magnetic film  60 . The upper electrode TE may include, for example, at least one of tungsten, titanium, tantalum, aluminum, or metallic nitrides (e.g., a titanium nitride or a tantalum nitride). The upper electrode TE may define a planar shape of a magnetic tunnel junction pattern which will be described below. 
     Referring to  FIG. 14 , a magnetic tunnel junction pattern MTJ may be formed by patterning the second magnetic film  60 , the insulation film  50 , and the first magnetic film  40  in sequence. For example, the second magnetic film  60 , the insulation film  50 , the first magnetic film  40 , and the lower electrode film BEL may be etched in sequence by using the upper electrode TE as an etching mask. Accordingly, a lower electrode BE, a first magnetic pattern  40 P, an insulation pattern  50 P, and a second magnetic pattern  60 P may be formed to be stacked on the lower interlayer insulation film  20  in sequence. 
     The magnetic tunnel junction pattern MTJ may include the first magnetic pattern  40 P, the insulation pattern  50 P, and the second magnetic pattern  60 P stacked on the lower electrode BE in sequence. The magnetic tunnel junction pattern MTJ may be electrically connected to the lower contact plug  30  through the lower electrode BE. 
     A protection film  70  may be formed to conformally cover side surfaces of the lower electrode BE, the magnetic tunnel junction pattern MTJ, and the upper electrode TE on the lower interlayer insulation film  20 . The protection film  70  may be extended on an upper surface of the lower interlayer insulation film  20 . The protection film  70  may include, for example, a silicon nitride film. 
     An upper interlayer insulation film  80  may be formed to cover the upper electrode TE and the protection film  70  on the lower interlayer insulation film  20 . The upper interlayer insulation film  80  may be a single layer or a multi-layer. For example, the upper interlayer insulation film  80  may include a silicone oxide film, a silicon nitride film, and/or a silicone oxynitride film, or the like. 
     A conductive pattern  90  may be formed on the upper interlayer insulation film  80 . The conductive pattern  90  may be extended in one direction and may be electrically connected with the plurality of magnetic tunnel junction patterns MTJ arranged along the one direction. The magnetic tunnel junction pattern MTJ may be electrically connected to the conductive pattern  90  through the upper electrode TE. 
     Referring to  FIG. 15 , in some example embodiments, each of a magnetization direction  40   m   1  of the first magnetic pattern  40 P and a magnetization direction  60   m   1  of the second magnetic pattern  60 P may be substantially parallel to interfaces of the insulation pattern  50 P and the second magnetic pattern  60 P. 
     Although  FIG. 15  illustrates that the first magnetic pattern  40 P is a pinned layer and the second magnetic pattern  60 P is a free layer, the present disclosure is not limited thereto. That is, in some other example embodiments, the first magnetic pattern  40 P may be a free layer and the second magnetic pattern  60 P may be a pinned layer. 
     Each of the first and second magnetic patterns  40 P,  60 P may include a ferromagnetic material. The first magnetic pattern  40 P may further include an antiferromagnetic material for fixing the magnetization direction of the ferromagnetic material in the first magnetic pattern  40 P. 
     Referring to  FIG. 16 , in some other example embodiments, each of a magnetization direction  40   m   2  of the first magnetic pattern  40 P and a magnetization direction  60   m   2  of the second magnetic pattern  60 P may be substantially perpendicular to the interfaces of the insulation pattern  50 P and the second magnetic pattern  60 P. 
     Although  FIG. 16  illustrates that the first magnetic pattern  40 P is a pinned layer and the second magnetic pattern  60 P is a free layer, the present disclosure is not limited thereto. That is, in some other example embodiments, the first magnetic pattern  40 P may be a free layer and the second magnetic pattern  60 P may be a pinned layer. 
     Each of the first and second magnetic patterns  40 P,  60 P having the perpendicular magnetization directions  40   m   2 ,  60   m   2  may include at least one of a perpendicular magnetic material (e.g., CoFeTb, CoFeGd, or CoFeDy), a perpendicular magnetic material having an L10 structure, CoPt of a hexagonal close packed lattice structure, and a perpendicular magnetic structure. The perpendicular magnetic material having the L10 structure may include at least one of FePt of the L10 structure, FePd of the L10 structure, CoPd of the L10 structure, or CoPT of the L10 structure. The perpendicular magnetic structure may include a magnetic film and insulation films which are stacked alternately and repeatedly. For example, the perpendicular magnetic structure may include at least one of (Co/Pt)n, (CoFe/Pt)n, (CoFe/Pd)n, (Co/Pd)n, (Co/Ni)n, (CoNi/Pt)n, (CoCr/Pt)n, or (CoCr/Pd)n (n is the number of times of stacking). 
     The present inventive concepts have been explained hereinabove with reference to some example embodiments with the drawings attached. It should be understood that the present inventive concepts are not limited to the aforementioned example embodiments, but may be fabricated in various different forms, and may be implemented by a person skilled in the art in other modified forms without altering the technical concepts or essential characteristics of the present inventive concepts. Accordingly, it will be understood that the example embodiments described above are only illustrative, and should not be construed as limiting.