Patent Publication Number: US-2018037983-A1

Title: Sputtering device

Description:
TECHNICAL FIELD 
     The present invention relates to a sputtering device. 
     BACKGROUND ART 
     Publicly known technologies for a sputtering device for improving film quality and processing efficiency are disclosed in Japanese Unexamined Patent Applications Laid-Open Nos. 11-335835, 2011-026652, 2003-183825, 7-307239, 10-317135, 2001-026869, and 2005-325433. For example, Japanese Unexamined Patent Application Laid-Open No. 10-317135 discloses a technique of depositing a film while a rotating workpiece revolves. 
     Optical components have various types of thin films deposited thereon in accordance with required optical characteristics. Optical components must be able to be made in a wide variety of small batch productions, in mass production of a few types, and in production for special severe-use environments, or for other requirements. Although techniques capable of satisfying any of these requirements are desired, conventional techniques have limited versatility. 
     DISCLOSURE OF THE INVENTION 
     In view of these circumstances, an object of the present invention is to provide a sputtering device capable of satisfying various requirements. 
     A first aspect of the present invention provides a sputtering device including a rotation and revolution table, multiple sputtering targets, and a load-lock chamber. The rotation and revolution table is positioned in a pressure-reducible container and is rotatable by independent control. The multiple sputtering targets are placed on a revolution orbit of the rotation and revolution table so as to correspond to multiple workpieces to be set on the rotation and revolution table. The load-lock chamber is used for setting the workpieces on the rotation and revolution table. The rotation and revolution table is configured by arranging multiple rotation mounts on a revolution table. The rotations of the revolution table and the multiple rotation mounts are independently controllable. 
     According to a second aspect of the present invention, in the invention according to the first aspect of the present invention, the multiple sputtering targets may be configured to be used in respective film depositing atmospheres that are separated from each other in the pressure-reducible container. 
     According to a third aspect of the present invention, in the invention according to the first or the second aspect of the present invention, the sputtering device may perform sputtering while the rotation mounts rotate and the revolution table swings back and forth on the revolution orbit. 
     According to a fourth aspect of the present invention, in the invention according to any one of the first to the third aspects of the present invention, the sputtering device is configured so that multiple carriers on which workpieces are mounted are placed in the load-lock chamber and so that the multiple carriers are rotated and revolved in different manners. 
     According to a fifth aspect of the present invention, in the invention according to any one of the first to the fourth aspects of the present invention, the load-lock chamber may be controlled independently from the pressure-reducible container so as to be reduced in pressure. 
     According to a sixth aspect of the present invention, in the invention according to any one of the first to the fifth aspects of the present invention, the sputtering device may further include a plasma source or a radical source provided on the revolution orbit of the rotation and revolution table, to perform plasma treatment or radical treatment on the multiple workpieces to be arranged on the rotation and revolution table. 
     Effects of the Invention 
     The present invention provides a sputtering device capable of satisfying various requirements. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a conceptual drawing of a sputtering device as seen from above. 
         FIG. 2  is a conceptual drawing of a sputtering device as seen from a side. 
         FIG. 3  is a conceptual drawing of an inside of a pressure-reducible container as seen from above. 
         FIG. 4  is a conceptual drawing showing an example of an operation mode. 
         FIG. 5  is a conceptual drawing showing an example of an operation mode. 
         FIG. 6  is a conceptual drawing showing a driving mechanism. 
         FIG. 7  is a conceptual drawing showing a structure of a sputtering section. 
         FIG. 8  is a conceptual drawing showing a structure of a sputtering section. 
     
    
    
     EXPLANATION OF REFERENCE NUMERALS 
       100  denotes a sputtering device,  101  denotes a pressure-reducible container,  102  denotes a load-lock chamber,  104  denotes a revolution table,  105  denotes a rotation mount,  106  denotes a carrier,  107  denotes a workpiece,  108  denotes a sputtering section,  109  denotes a sputtering section,  110  denotes a plasma processing section,  111  denotes a sputtering target,  112  denotes a high frequency power source,  113  denotes a partition,  113   a  denotes a wall,  113   b  denotes a sealing part,  114  denotes a reaction space,  150  denotes a driving mechanism,  151  denotes a sun gear,  152  denotes a planetary gear,  153  denotes a planetary carrier,  154  denotes an outer gear, and  155  denotes an outer driving gear. 
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Structure 
       FIGS. 1 and 2  show a sputtering device  100  of an embodiment. The sputtering device  100  has a pressure-reducible container  101  and a load-lock chamber  102 . The pressure-reducible container  101  is airtight and is configured so that its internal pressure is reduced by a vacuum pump (not shown). The load-lock chamber  102  connects to the pressure-reducible container  101  via a gate valve and has an airtight structure similar to that of the pressure-reducible container  101 . The load-lock chamber  102  is also connected to a vacuum pump and is configured so that its internal pressure is controlled separately from the pressure-reducible container  101 . 
     As shown in  FIG. 3 , the pressure-reducible container  101  has a revolution table  104  placed inside thereof. The revolution table  104  has eight rotation mounts  105  that are arranged on a circumference centered at the rotation center of the revolution table  104 . The revolution table  104  and the rotation mounts  105  constitute a rotation and revolution table. The revolution table  104  and the rotation mounts  105  are rotatable independently from each other. 
     The rotation mounts  105  are approximately circular and rotate around its center. The rotation mounts  105  may rotate in a clockwise direction, in a counterclockwise direction, or in clockwise and counterclockwise directions, such as in a swinging manner. The rotations of the rotation mounts  105  are called “rotations” in the specification of the present invention. The rotation direction is specified as a direction as seen from above. The revolution table  104  is also approximately circular and rotates around its center. Rotation of the revolution table  104  makes the rotation mounts  105  revolve on the rotation center of the revolution table  104 . The revolution table  104  may also rotate in a clockwise direction, in a counterclockwise direction, or in clockwise and counterclockwise directions, such as in a swinging manner. 
     The rotation mounts  105  are each configured so that a carrier  106  is arranged thereon. The carrier  106  holds workpieces  107  to be deposited, for example, holds optical parts, such as lenses. In this embodiment, the carrier  106  is able to accommodate seven workpieces  107 . The workpieces  107  are not limited to optical parts. Although an exemplary case of depositing an optical thin film is described in this embodiment, the thin film to be deposited may be any type of coating film, including a metal film, an insulating film, and a semiconductor film. 
       FIGS. 4 and 5  conceptually show operation states of the revolution table  104  and the rotation mounts  105 .  FIG. 4  shows a case of rotating the revolution table  104  and the rotation mounts  105  in the clockwise direction. The carriers  106  (refer to  FIG. 3 ) on the rotation mounts  105  each rotate around the rotation centers of the respective rotation mounts  105  and each revolve around the rotation center of the revolution table  104 . The mode shown in  FIG. 4  is called a “revolving rotation mode”. The combination of the rotation direction and the revolution direction in the revolving rotation mode shown in  FIG. 4  may be selected as desired. The combination of the rotation speed and the revolution speed may also be selected as desired. 
       FIG. 5  shows a case of rotating the revolution table  104  in the clockwise and counterclockwise directions in a swinging manner and rotating the rotation mounts  105  in the clockwise direction. The carriers  106  (refer to  FIG. 3 ) on the rotation mounts  105  each rotate while swinging back and forth on their revolution orbit. The mode shown in  FIG. 5  is called a “swinging rotation mode”. The combination of the swinging range, the swinging speed, the rotation direction, and the rotation speed in the swinging rotation mode shown in  FIG. 5  may be selected as desired. 
     The following describes a driving mechanism for rotating the revolution table  104  and the rotation mounts  105 .  FIG. 6  shows a driving mechanism  150  constituting a driving system. The driving mechanism  150  is a planetary gear mechanism having a sun gear  151 , four planetary gears  152 , a planetary carrier  153 , an outer gear  154 , and an outer driving gear  155 . 
     The sun gear  151  is driven and rotated by a first motor (not shown). The four planetary gears  152  engage with the sun gear  151  and are rotatably attached on the circular planetary carrier  153 . Although four planetary gears  152  are described in  FIG. 6  to simplify the drawing, eight planetary gears  152  may be used to correspond to the structure shown in  FIG. 3 . 
     The four planetary gears  152  engage with the circular outer gear  154  that is positioned at the outside of the four planetary gears  152 . The outer gear  154  is formed with teeth at an inner circumferential side and an outer circumferential side, and its inside teeth engage with the four planetary gears  152  whereas its outside teeth engage with the outer driving gear  155 . The outer driving gear  155  is driven and rotated by a second motor (not shown). The first motor for driving the sun gear  151  and the second motor for driving the outer driving gear  155  are rotatable independently from each other. 
     The rotation shaft of each of the planetary gears  152  connects with a rotation shaft serving as a rotation axis of the rotation mount  105  shown in  FIG. 3 , and thus, rotation of each of the planetary gears  152  makes the corresponding rotation mount  105  rotate. The revolution table  104  is fixed over the planetary carrier  153 . Rotation of the planetary carrier  153  makes the revolution table  104  rotate, thereby making the rotation mounts  105  revolve. As described later, the movement mode of the rotation mounts  105  can be selected from (1) rotation without revolution, (2) revolution without rotation, (3) revolution and rotation (revolving rotation mode), and (4) swinging and rotation (swinging rotation mode). 
     The following describes a principle of independent control of the rotations of the rotation mounts  105  and the revolution table  104 . Assuming that angular velocity and the number of teeth of the sun gear  151  are respectively represented by ωa and Za, angular velocity and the number of teeth of the planetary gear  152  are respectively represented by cob and Zb, angular velocity and the number of teeth of the outer gear  154  are respectively represented by ωc and Zc, and angular velocity of the planetary carrier  153  is represented by ωx, the following First Formula and Second Formula are satisfied on the basis of the fundamental principle of the planetary gear. 
     
       
         
           
             
               
                 
                   
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     The rotation direction and the value of ωa are determined by driving control of the first motor. The rotation direction and the value of we are determined by driving control of the second motor. 
     The values of ωa and ωe are selected so that the value of ωx=0 in the First Formula and Second Formula, whereby the planetary gears  152  are rotated at the angular velocity cob without rotating the planetary carrier  153 . Thus, the movement mode (1) is operated, and the rotation mounts  105  rotate without revolving. 
     The values of ωa and ωe are selected so that the value of ωb=0 in the First Formula and Second Formula, whereby the planetary carrier  103  is rotated at the angular velocity ωx without rotating the planetary gears  152 . Thus, the movement mode (2) is operated, and the rotation mounts  105  revolve without rotating. 
     The values of ωa and ωe are selected so that the values of ωx and cob will not be zero in the First Formula and Second Formula, whereby the planetary gears  152  are rotated at the angular velocity ωb while the planetary carrier  103  is rotated at the angular velocity ωx. Thus, the movement mode (3) is operated, and the rotation mounts  105  rotate while revolving. 
     In the condition in which the values of ωx and cob are not zero, the value of cob may be set to be less than or greater than 1, and the values of wa and we may be controlled so that the value of ωx will periodically fluctuate to be positive or negative. In this case, the movement mode (4) is operated, and the rotation mounts  105  rotate while their rotation centers swing back and forth on their revolution orbit. 
     In the movement mode (1) or the movement mode (4), the value of cox may be controlled to move a specific rotation mount  105  or a specific carrier  106  to a desired position on the revolution orbit. 
     To return to  FIG. 1 , the sputtering device  100  also has a sputtering section  108 , a sputtering section  109 , and a plasma processing section  110 . The sputtering section  108 , the sputtering section  109 , and the plasma processing section  110  are arranged on the revolution orbit of the rotation mounts  105 . The sputtering section  108  and the sputtering section  109  have the same structure. The sputtering target is selected in accordance with a desired film to be deposited. For example, the sputtering section  108  may perform deposition of a first thin film, and the sputtering section  109  may perform deposition of a second thin film. Alternatively, the sputtering sections  108  and  109  may perform deposition of the same type of thin film. 
     The following describes details of the sputtering sections  108  and  109 . Since the sputtering sections  108  and  109  have the same structure, only the sputtering section  108  will be described here.  FIG. 7  shows a sectional structure of the sputtering section  108 . It is noted that  FIG. 7  does not show the driving system, which is described by referring to  FIG. 6 . 
     The sputtering section  108  has a sputtering target  111 . The sputtering target  111  is attached on a back surface side of a top cover  101   a  of the pressure-reducible container  101 . The sputtering target  111  connects to a high frequency power source  112 . The sputtering section  108  may be configured to perform direct current (DC) sputtering, as shown in  FIG. 8 . In this structure, as shown in  FIG. 8 , a DC power source  115  is connected as a power source. 
     The carrier  106  is placed on the rotation mount  105  so as to face the sputtering target  111 . As the revolution table  104  rotates, the carrier  106  also moves on the revolution orbit, and therefore, the carrier  106  may not be located at the position shown in  FIG. 7 .  FIG. 7  shows a state in which the carrier  106  is stopped at the described position by controlling the value of ωx as described above. Although the carrier  106  has the workpieces  107  mounted thereon as shown in  FIG. 2 , the workpieces  107  are not shown in  FIG. 7 . 
     The top cover  101   a  is provided with partitions  113 . The partitions  113  separate a film deposition atmosphere in a reaction space  114  from a film deposition atmosphere in an adjacent reaction space. The same or similar structure as the partitions  113  are also provided to the sputtering section  109  and the plasma processing section  110 . 
     Sputtering film deposition may be performed by supplying gas of an element for sputtering, gas of an element to be reacted with a sputtered material, and other necessary gas, from a gas supplying system (not shown) into the reaction space  114 . For example, a silicon compound film may be deposited. In this case, a silicon target is used as the sputtering target  111 , and argon gas, oxygen gas, and nitrogen gas are supplied into the reaction space  114 . Then, a vacuum pump (not shown) is started to reduce the pressure in the reaction space  114  to a desired degree. Next, the argon gas is ionized by high frequency electric power from the high frequency power source  112 , and sputtering is performed. Thus, the material composing the sputtering target  111  is deposited on a surface of the respective workpieces  107  (refer to  FIG. 3 ) arranged on the carrier  106  to generate a thin film. Meanwhile, the reactive gas reacts, and reactive sputtering is performed. The film deposition operation may also be performed in the sputtering section  109 . The plasma processing section  110  has a radio frequency (RF) plasma source that generates RF plasma by high frequency discharging, and the plasma processing section  110  may perform etching treatment using plasma etching gas, film oxidizing treatment using oxygen plasma, or film nitriding treatment using nitrogen plasma. As an alternative to the plasma processing section  110 , a structure using a radical source for supplying iron source may be configured to perform radical treatment. 
     The load-lock chamber  102  is configured to contain the workpieces  107  (refer to  FIG. 3 ) arranged on the carrier  106 . The workpieces  107  or the carrier  106  is moved between the load-lock chamber  102  and the pressure-reducible container  101  by a robot arm (not shown). As shown in  FIG. 2 , multiple carriers  106 , on which the workpieces  107  are mounted, are stacked in a vertical direction and are contained in the load-lock chamber  102 . The load-lock chamber  102  is provided with an elevator to vertically move the carrier  106 . 
     First Exemplary Operation 
     An exemplary case of performing continuous film deposition in the movement mode (1) will be described hereinafter. In this case, a silicone oxide film is deposited as a first optical thin film on a lens in the sputtering section  108 , and then a niobium oxide film is deposited as a second optical thin film in the sputtering section  109 . The silicon oxide film of the first optical thin film and the niobium oxide film of the second optical thin film are alternately laminated in a multilayered manner to coat the lens, which is a workpiece, with a desired optical thin film. 
     First, a carrier  106  on which workpieces  107  (refer to  FIG. 3 ) are mounted is placed on a rotation mount  105  shown in  FIG. 4 . The revolution table  104  is then rotated, and the first optical thin film is deposited on each of the workpieces  107  in the sputtering section  108  in a condition as shown in  FIG. 7 . After the first optical thin film is deposited, the revolution table  104  is rotated to move the carrier  106  into the sputtering section  109 . Then, sputtering is performed while the rotation mount  105  rotates, to deposit the second optical thin film with respect to each of the workpieces  107  in the sputtering section  109 . 
     The deposition of the first optical thin film and the deposition of the second optical thin film are alternately repeated “n” times. Consequently, a multilayered optical thin film is formed on each of the seven workpieces  107  (refer to  FIG. 3 ) on the specific carrier  106  by alternately laminating “n” numbers of the silicon oxide films as the first optical thin films and the niobium oxide films as the second optical thin films. 
     The following processing steps are repeated during the above operation. 
     (1) While the film deposition is performed in the pressure-reducible container  101 , eight carriers  106  holding seven untreated workpieces  107  are put in the load-lock chamber  102 .
 
(2) The load-lock chamber  102  is then evacuated. During the film deposition in the pressure-reducible container  101 , the gate valve is closed to separate the load-lock chamber  102  and the pressure-reducible container  101 .
 
(3) After the film deposition is finished in the pressure-reducible container  101 , the pressure in the pressure-reducible container  101  is set to be the same pressure in the load-lock chamber  102 . Then, the gate valve separating the load-lock chamber  102  and the pressure-reducible container  101  is opened to enable moving out of the carrier  106  from the pressure-reducible container  101  to the load-lock chamber  102  and moving in a next carrier  106 , on which workpieces  107  without films are mounted, from the load-lock chamber  102  to the pressure-reducible container  101 . Thus, the treated workpieces  107  in the pressure-reducible container  101  are replaced with untreated workpieces  107  in the load-lock chamber  102 .
 
(4) After the workpieces  107  are replaced, the gate valve is closed to separate the load-lock chamber  102  and the pressure-reducible container  101 , and the untreated workpieces  107  are subjected to the film deposition treatment. During the film deposition treatment, the already-treated workpieces  107  in the load-lock chamber  102  are moved out to the outside of the device, and the processing step (1) is started.
 
     The processing steps (1) to (4) are repeated, whereby the processing is continuously performed, and an optical thin film is formed on each of the workpieces  107  (lenses) with high productivity. The film deposition is performed in a small area immediately under the sputtering source, thereby enabling high speed film deposition. 
     Second Exemplary Operation 
     Batch processing for integrally treating multiple workpieces simultaneously will be described hereinafter. In this case, each of the carriers  106  is rotated while the revolution table  104  rotates at a constant rate. Each of the carriers  106  rotates while revolving. When a specific carrier  106  passes through the sputtering section  108 , the film deposition of the first optical thin film is performed on workpieces  107  on the specific carrier  106 . The specific carrier  106  then passes through the sputtering section  109 , and meanwhile, the film deposition of the second optical thin film is performed. Thereafter, while the specific carrier  106  passes through the plasma processing section  110 , the plasma treatment is performed. These three treatments are uniformly performed on each of the carriers  106  on the rotating revolution table  104 . The sputtering sections  108  and  109  and the plasma processing section  110  may be controlled independently from each other or may be controlled at the same time. Such a structure enables depositing a mixed film made of target materials in the sputtering sections  108  and  109 . Extremely thin films may be respectively deposited in the sputtering sections  108  and  109  and may be subjected to the plasma treatment at the same time. 
     The film deposition and the plasma treatment are repeated “n” times while the revolution table  104  rotates “n” times, whereby a multilayered optical thin film is formed on a surface of each of the workpieces  107  by alternately laminating “n” numbers of the silicon oxide films as the first optical thin films and the niobium oxide films as the second optical thin films. This processing enables integrally treating multiple workpieces uniformly at the same time and is thus called “batch processing”. The replacement of the workpieces  107  using the load-lock chamber  102  may be performed in the same manner as in the First Exemplary Operation. 
     Third Exemplary Operation 
     The movement mode (4) may be performed in the First Exemplary Operation and Second Exemplary Operation. In this case, when the carrier  106  and the sputtering target  111  have the positional relationship as shown in  FIG. 7 , the film deposition is performed while the revolution table  104  swings as shown in  FIG. 5  and the rotation mount  105  rotates. The movement mode (4) is operated so that the rotation center will swing back and forth on the revolution orbit, and therefore, a highly uniform film is deposited. 
     Fourth Exemplary Operation 
     Although the same optical thin film is deposited on each of the workpieces  107  on the multiple carriers  106  in the First to Third Exemplary Operations, optical thin films having different optical characteristics from each other may be respectively deposited on the workpieces  106  on each carrier  106 . The sputtering device  100  enables forming an optical thin film by alternately laminating the first optical thin films, which are deposited in the sputtering section  108 , and the second optical thin films, which are deposited in the sputtering section  109 . The optical characteristics are controlled by changing the thickness relationship between the first optical thin film and the second optical thin film in this method. 
     For example, a laminated layer having a first combination may be obtained in a first carrier  106 , and a laminated layer having a second combination may be obtained in a second carrier  106 . That is, optical thin films having different film quality from each other are respectively obtained in the carriers  106 . The optical characteristics are controlled by adjusting one or more controlling elements such as a rotation speed of the revolution table  104 , a swinging cycle, a swinging amplitude width, a rotation speed of the rotation mounts  105 , sputtering discharge conditions, and a film deposition time. The sputtering device  100  is configured so that the revolution table  104  and the rotation mounts  105  are controllable independently from each other, and therefore, the film deposition condition is easily changed with respect to each of the carriers  106 .