Abstract:
A manipulator assembly in an ion implanter comprises a ground electrode, a first suppression electrode located on a first side of the ground electrode facing an ion source device for producing ion beams, a second suppression electrode which is located on a second side of the ground electrode opposite to the first side, connection legs which electrically connect and mechanically support the first and second suppression electrodes; and an insulator which is located between the ground electrode and the second suppression electrode to insulate the ground electrode from the first and second suppression electrodes.

Description:
BACKGROUND OF THE INVENTION 
   This application claims the priority of Korean Patent Application No. 2003-100495, filed on Dec. 30, 2003, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
   1. Field of the Invention 
   The present invention relates to an ion implanter used for manufacturing a semiconductor device, and more particularly, to a manipulator assembly in an ion implanter. 
   2. Description of the Related Art 
   An ion implanter is used to dope semiconductor wafers with impurities in the manufacture of a semiconductor device. The ion implanter includes an ion source portion which produces ion beams with which the semiconductor wafer is to be doped, and a manipulator assembly which focuses the ion beams. The ion beams pass through the manipulator assembly, undergo various filtering processes, and are implanted into the semiconductor wafer. 
     FIG. 1  is a schematic view for illustrating an ion source portion, and a manipulator assembly in an ion implanter, according to the prior art, and  FIG. 2  is a perspective view of the manipulator assembly in the ion implanter of  FIG. 1 . 
   Referring to  FIGS. 1 and 2 , the ion implanter includes an ion source portion  100  which produces ion beams IB, and a manipulator assembly  200  which is adjacent to the ion source portion  100 , and focuses the ion beams IB. 
   The ion source portion  100  includes an arc chamber  102  which arc-discharges a supplied source gas to produce the ion beams IB. The ion beams IB are discharged through a first hole  104  which is provided on a side of the arc chamber  102 . 
   The manipulator assembly  200  includes a ground electrode  202 . First and second suppression electrodes  204  and  206  are positioned at predetermined distances from the left and right sides of the ground electrode  202 , respectively. The first and second suppression electrodes  204  and  206  are electrically interconnected and supported by connection legs  208 . The first suppression electrode  204  keeps a distance L 1  from the ground electrode  202 , and the second suppression electrode  206  keeps a distance L 2  from the ground electrode  202 . The distance L 2  is longer than the distance L 1 . 
   Insulators  210  are positioned between the first suppression electrode  204  and the ground electrode  202 . A voltage difference between the first and second suppression electrodes  204  and  206  and the ground electrode  202  is kept at about 5 kV during implantation of the ion beams IB. A ground shield  212  is attached to a side of the ground electrode  202  so that the ion beams IB are not adhered onto the ground electrode  202 . 
   The ion beams IB are supplied to a second hole  214  made in the first suppression electrode  204  of the manipulator assembly  200  via the first hole  104  of the arc chamber  102 . The ion beams IB are controlled, focused, and discharged via a third hole  216  made in the ground electrode  202  and a fourth hole  218  made in the ground shield  212 . 
     FIG. 3  is a graph for showing variations in a suppression current with respect to the time required for using the ion implanter of  FIGS. 1 and 2 . 
   As described above, the manipulator assembly  200  in the ion implanter of  FIGS. 1 and 2  insulates the first suppression electrode  204  from the second suppression electrode  206  using the insulators  210 . Also, the voltage difference between the first suppression electrode  204  and the ground electrode  202  is kept at about 5 kV. However, as impurities are implanted into a plurality of portions of a semiconductor wafer using the ion implanter, i.e., the ion implanter is used for a long period of time, the ion beams IB are deposited on the insulators  210 . This leads to a reduction in a resistance of the insulators  210 , which results in increasing the suppression current as marked with ⋄. Thus, the manipulator assembly  200  must be periodically overhauled to overcome this problem. 
   SUMMARY OF THE INVENTION 
   The present invention provides a manipulator assembly in an ion implanter capable of preventing ion beams from being depositing on insulators between a suppression electrode and a ground electrode so as to prevent a suppression current from increasing. 
   According to an aspect of the present invention, there is provided a manipulator assembly in an ion implanter, including a ground electrode; a first suppression electrode located on a first side of the ground electrode facing an ion source device which produces ion beams; a second suppression electrode which is located on a second side of the ground electrode opposite to the first side; connection legs which electrically connect and mechanically support the first and second suppression electrodes; and 
   an insulator which is located between the ground electrode and the second suppression electrode to insulate the ground electrode from the first and second suppression electrodes. 
   The manipulator assembly in the ion implanter may further include a ground shield which is installed to face the second suppression electrode so as to prevent the ion beams from being deposited on a side of the ground electrode. A distance between the ground electrode and the second suppression electrode may be longer than a distance between the ground electrode and the first suppression electrode. 
   According to another aspect of the present invention, there is provided a manipulator assembly in an in implanter, including: a ground electrode; a first suppression electrode which is installed in front of the ground electrode to face a source part which produces ion beams; a second suppression electrode which is installed in the rear of the ground electrode; connection legs which electrically connect and mechanically support the first and second suppression electrodes; insulators which are installed between the ground electrode and the second suppression electrode to insulate the ground electrode from the first and second suppression electrodes; and first and second cup shields which are installed to prevent the ion beams from being deposited around the insulators. 
   The first cup shield may be installed on the ground electrode, and the second cup shield may be installed on the second suppression electrode. The manipulator assembly in the ion implanter may further include a ground shield which is installed to face the second suppression electrode so as to prevent the ion beams from being deposited on a side of the ground electrode. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
       FIG. 1  is a schematic view for explaining an ion implantor, and a manipulator assembly in the ion implanter, according to the prior art; 
       FIG. 2  is a perspective view of the manipulator assembly in the ion implanter of  FIG. 1 ; 
       FIG. 3  is a graph for showing variations in a suppression current with respect to the time required for using the ion implanter of  FIGS. 1 and 2 ; 
       FIG. 4  is a schematic view of a source part and a manipulator assembly in an ion implanter, according to an embodiment of the present invention; 
       FIG. 5  is a perspective view of the manipulator assembly in the ion implanter of  FIG. 4 ; 
       FIGS. 6 and 7  are perspective views of a manipulator assembly, according to different embodiments of the present invention; 
       FIG. 8  is a schematic view for explaining the manipulator assembly in the ion implanter according to the present invention; and 
       FIG. 9  is a schematic cross-sectional view for explaining the cup shields of the insulators of the manipulator assembly in the ion implanter according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the invention to those skilled in the art. 
   Referring to  FIGS. 4 and 5 , the ion implanter includes an ion source device  300  which produces ion beams IB, and a manipulator assembly  400  which is adjacent to the ion source device  300  and focuses the ion beams IB. 
   The ion source device  300  includes an arc chamber  302  which discharges a supplied source gas to produce the ion beams IB. The ion beams IB are discharged via a first hole  304  which is provided on a side of the arc chamber  302 . 
   The manipulator assembly  400  includes a ground electrode  402 . The ground electrode  402  is formed of graphite or the like. First and second suppression electrodes  404  and  406  are positioned at predetermined distances from the left and right sides of the ground electrode  402 . In other words, the first suppression electrode  404  is positioned in front of the ground electrode  402  so as to face the ion source device  300  which produces the ion beams IB. The second suppression electrode  406  is positioned in the rear of the ground electrode  402 . 
   The first and second suppression electrodes  404  and  406  are electrically interconnected and supported by connection legs  408 . A distance L 1  between the ground electrode  402  and the first suppression electrode  404  and a distance L 2  between the ground electrode  402  and the second suppression electrode  406  are kept as in the manipulator assembly according to the prior art. 
   Unlike the manipulator assembly of the prior art, in the manipulator assembly according to the present invention, insulators  410  are positioned between the second suppression electrode  406  and the ground electrode  402 . A voltage difference between the first and second suppression electrodes  404  and  406  and the ground electrode  402  is kept at about 5 kV during implantation of the ion beams IB. In other words, a −5 kV voltage is applied to the first and second suppression electrodes  404  and  406  and the ground electrode  402  is ground to maintain a voltage difference therebetween. A ground shield  412  is attached to a side of the ground electrode  402  so as not to stick the ion beams IB on the ground electrode  402 . 
   The ion beams IB are supplied via a first hole  304  made in a side of the arc chamber  302 , and a second hole  414  made in the center of the first suppression electrode  404  of the manipulator assembly  400 . Next, the ion beams IB are controlled, focused, and discharged via a third hole  416  made in the ground electrode  402  and a fourth hole  418  made in the ground shield  412 . 
   As described previously, in the manipulator assembly of the ion implanter according to the present invention, the distance L 1  between the ground electrode  402  and the first suppression electrode  404  and the distance L 2  between the ground electrode  402  and the second suppression electrode  406  are kept as in the manipulator assembly according to the prior art. Also, the insulators  410  are installed between the second suppression electrode  406  and the ground electrode  402  to insulate the ground electrode  402  from the first and second suppression electrodes  404  and  406 . 
   Accordingly, the insulators  410  can be longer than the insulators  210  according to the prior art, which resulting in increasing a resistance of the insulators  410 . As a result, the period for overhauling the implanter assembly can be increased. In other words, although the ion beams IB are deposited on the insulators  410  due to implantation of impurities into a plurality of pieces of semiconductor wafer using the ion implanter, the period for overhauling the manipulator assembly can be long due to the great resistance of the insulators  410 . 
     FIGS. 6 and 7  are perspective views of a manipulator assembly, according to different embodiments of the present invention. Reference numerals of  FIGS. 6 and 7  denote the same elements as those of  FIGS. 4 and 5 . For convenience, a ground shield is not shown. 
   The first suppression electrode  404  is positioned upward in  FIG. 6 , while the second suppression electrode  406  is positioned upward in  FIG. 7 . As previously described, the insulators  410  are installed between the first and second suppression electrodes  404  and  406 , and the ground electrode  402  to insulate the ground electrode  402  from the first and second suppression electrodes  404  and  406 . As shown in  FIGS. 6 and 7 , three insulators  410  are installed in the form of pillar. However, three insulators may be installed in a different configuration if desired. 
   As shown in  FIG. 8 , the first and second suppression electrodes  404  and  406  are positioned at the left and right sides of the ground electrode  402 . The first and second suppression electrodes  404  and  406  are electrically interconnected via the connection legs  408 . As previously described, the insulators  410  are installed between the second suppression electrode  406  and the ground electrode  402  to insulate the ground electrode  402  from the first and second suppression electrodes  404  and  406 . 
   As shown in  FIG. 9 , first and second cup shields  420  and  422  are installed to prevent ion beams from being deposited around the insulators  410  between the second suppression electrode  406  and the ground electrode  402  during implantation of ions. The first cup shield  420  is installed on the ground electrode  402 , and the second cup shield  422  is installed on the second suppression electrode  406 . The first and second cup shields  420  and  422  are insulated from each other. The installation of the second cup shield  422  around the insulators  410  can prevent ion beams from being deposited on the insulators  410  so as to prevent a reduction in the resistance of the insulators  410 . 
   As described above, in the manipulator assembly of the ion implanter according to the present invention, distances between the ground electrode  402  and the first and second suppression electrodes  404  and  406  are kept as in the implanter assembly according to the prior art. Also, the insulators  410  are installed between the second suppression electrode  406  and the ground electrode  402  to increase the resistance of the insulators  410 . Moreover, the second cup shield  422  is installed around the insulators  410  to prevent ion beams from being deposited on the insulators  410  so as to minimize the reduction in the resistance of the insulators  410 . 
   As a result, the manipulator assembly of the ion implanter according to the present invention can increase the period for overhauling itself by preventing the reduction in the resistance of the insulators  410  which insulate the ground electrode  402  from the first and second suppression electrodes  404  and  406 . 
   As described above, in a manipulator assembly of an ion implanter according to the present invention, insulators can be installed between a second suppression electrode and a ground to increase a resistance of the insulators. Furthermore, a cup shield is installed around the insulators to prevent ion beams from being deposited on the insulators so as to minimize the resistance of the insulators. As a result, an increase in a suppression current can be minimized to thereby increase the period for overhauling the manipulator assembly. 
   While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.