Patent Publication Number: US-8993979-B2

Title: Beam control assembly for ribbon beam of ions for ion implantation

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a Continuation application of U.S. patent application Ser. No. 13/889,278, filed May 7, 2013, which issued as U.S. Pat. No. 8,680,480 on Mar. 25, 2014, which is a Continuation application of U.S. patent application Ser. No. 12/957,294, filed Nov. 30, 2010, which issued as U.S. Pat. No. 8,502,160 on Aug. 6, 2013, which is a Continuation application of U.S. patent application Ser. No. 12/053,076, filed Mar. 21, 2008, which issued as U.S. Pat. No. 7,851,767 on Dec. 14, 2010, which claims priority to U.S. Provisional Application Ser. No. 60/919,365, filed Mar. 21, 2007, which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     1. Field 
     The present application generally relates to ion implanters, and, more particularly, to a beam control assembly to shape a ribbon beam of ions for ion implantation. 
     2. Related Art 
     Ion implanters are used to implant ions in various applications, including semiconductor device fabrication. As depicted in  FIG. 1 , an ion implanter  100  typically includes an ion source  102  configured to generate the ions, an accelerator  104  configured to accelerate the ions to a desired energy, a beam control assembly  106  configured to shape the ions into a desired pattern, and a target area  108  configured to position the work piece, such as a wafer in semiconductor device fabrication, for ion implantation. 
     To increase throughput, particularly in semiconductor applications, a ribbon beam of ions is used. In particular, with reference to  FIG. 2A , a ribbon beam  202  can be generated and used to implant ion in an area of a work piece, such as a wafer in semiconductor applications. As depicted in  FIG. 2A , ribbon beam  202  has a beam width  204  and travels in a beam direction  206 . 
     Various conventional devices and techniques exist for controlling ribbon beam  202 . For example, see, U.S. Pat. No. 7,078,713, issued Jul. 18, 2006, and U.S. Pat. No. 6,933,607, issued Aug. 23, 2005, which are incorporated herein by reference in their entireties for all purposes. These conventional devices and techniques have various shortcomings in shaping a ribbon beam of ions for ion implantation. 
     SUMMARY 
     In one exemplary embodiment, a beam control assembly to shape a ribbon beam of ions for ion implantation includes a first bar, second bar, first coil of windings of electrical wire, second coil of windings of electrical wire, first electrical power supply, and second electrical power supply. The first coil is disposed on the first bar. The first coil is the only coil disposed on the first bar. The second bar is disposed opposite the first bar with a gap defined between the first and second bars. The ribbon beam travels between the gap. The second coil is disposed on the second bar. The second coil is the only coil disposed on the second bar. The first electrical power supply is connected to the first coil without being electrically connected to any other coil. The second electrical power supply is connected to the second coil without being electrically connected to any other coil. 
    
    
     
       DESCRIPTION OF DRAWING FIGURES 
       The present application can be best understood by reference to the following description taken in conjunction with the accompanying drawing figures, in which like parts may be referred to by like numerals: 
         FIG. 1  depicts an ion implanter; 
         FIG. 2A  depicts a ribbon beam of ions; 
         FIGS. 2B and 2C  depict an exemplary beam control assembly; 
         FIGS. 3A-3C  depict another exemplary beam control assembly; 
         FIGS. 4-9  depict various exemplary beam control assemblies; and 
         FIG. 10  depicts an exemplary bar that can be used in an exemplary beam control assembly. 
     
    
    
     DETAILED DESCRIPTION 
     The following description sets forth numerous specific configurations, parameters, and the like. It should be recognized, however, that such description is not intended as a limitation on the scope of the present invention, but is instead provided as a description of exemplary embodiments. 
     With reference to  FIG. 2B , in one exemplary embodiment, a beam control assembly  208  to shape a ribbon beam of ions for ion implantation includes a first bar  210  and a second bar  212 . Second bar  212  is disposed opposite first bar  210  to define a gap  214  between second bar  212  and first bar  210 . The ribbon beam travels between gap  214 . 
     As depicted in  FIG. 2A , a first dimension  216  within beam control assembly  208  corresponds to beam width  204 . As also depicted in  FIG. 2A , a second dimension  218  within beam control assembly  208  corresponds to beam direction  206 . 
     In one exemplary embodiment, first bar  210  is located at a first position  220  in second dimension  218  and extends into first dimension  216 . In this exemplary embodiment, as depicted in  FIGS. 2B and 2C , second bar  212  is also located at first position  220  in second dimension  218  and extends into first dimension  216 . Alternatively, as depicted in  FIG. 4 , second bar  212  can be located at a second position  402  in second dimension  218 , which is different than first position  220 . 
     With reference to  FIG. 2A , beam control assembly  208  includes a first coil  222  disposed on first bar  210 . In the present exemplary embodiment, first coil  222  is the only coil disposed on first bar  210 . First coil  222  includes windings of electrical wire. As depicted in  FIG. 2C , the windings of first coil  222  are concentric to first bar  210 , which corresponds to being wound around first dimension  216  ( FIG. 2A ). 
     With reference again to  FIG. 2B , beam control assembly  208  includes a second coil  224  disposed on second bar  212 . In the present exemplary embodiment, second coil  224  is the only coil disposed on second bar  212 . Second coil  224  includes windings of electrical wire. As depicted in  FIG. 2C , the windings of second coil  224  are concentric to second bar  212 , which corresponds to being wound around first dimension  216  ( FIG. 2A ). 
     With reference again to  FIG. 2B , beam control assembly  208  includes a first electrical power supply  226  electrically connected to first coil  222  without being electrically connected to any other coil. Beam control  208  also includes a second electrical power supply  228  electrically connected to second coil  224  without being electrically connected to any other coil. 
     With reference to  FIG. 2B , in one exemplary embodiment, first coil  222  is fixed to first position  230  in first dimension  216  on first bar  210 . In this exemplary embodiment, second coil  224  is also fixed to first position  230  in first dimension  216  on second bar  212 . Second coil  224  is located opposite first coil  222  at first position  230  in first dimension  216 . Thus, the portion of ribbon beam  202  adjacent to first position  230  in first dimension  216  can be controlled from both sides of gap  214  using first coil  222  and first electrical power supply  226  and/or second coil  224  and second electrical power supply  228 . 
     With reference to  FIG. 5 , in another exemplary embodiment, second coil  224  can be fixed to a second position  502  in first dimension  216  on second bar  212 . In this exemplary embodiment, one portion of ribbon beam  202  adjacent to first position  230  in first dimension  216  can be controlled from one side of gap  214  using first coil  222  and first electrical power supply  226 , and another portion of ribbon beam  202  adjacent to second position  502  can be controlled from another side of gap  214  using second coil  224  and second electrical power supply  228 . 
     With reference to  FIG. 2B , in another exemplary embodiment, first coil  222  is configured to move along first bar  210  to be located at different positions in first dimension  216 . Second coil  224  is configured to move along second bar  212  to be located at different positions in first dimension  216 . Although not depicted, it should be recognized that first coil  222  and second coil  224  can be moved using various devices, including actuators, tracks, and the like. 
     With reference to  FIG. 3B , in on exemplary embodiment, beam control assembly  208  includes a third bar  302  and a fourth bar  304 . Fourth bar  304  is disposed opposite third bar  302  with gap  214  defined between fourth bar  304  and third bar  302 . The ribbon beam travels between gap  214 . 
     As depicted in  FIGS. 3A and 3C , third bar  302  is adjacent first bar  210 . Third bar  302  is located at a third position  306  in second dimension  218  and extends into first dimension  216 . In one exemplary embodiment, as depicted in  FIGS. 3B and 3C , fourth bar  304  is located at third position  306  in second dimension  218  and extends into first dimension  216 . Alternatively, as depicted in  FIG. 6 , fourth bar  304  can be located at fourth position  602  in second dimension  218 . 
     With reference to  FIG. 3A , beam control assembly  208  also includes a third coil  308  disposed on third bar  302 . In the present exemplary embodiment, third coil  308  is the only coil disposed on third bar  302 . Third coil  308  includes windings of electrical wire. As depicted in  FIG. 3C , the windings of third coil  308  are concentric to third bar  302 , which corresponds to being wound around first dimension  216  ( FIG. 3A ). 
     Beam control assembly  208  includes a fourth coil  310  disposed on fourth bar  304 . In the present exemplary embodiment, fourth coil  310  is the only coil disposed on fourth bar  304 . Fourth coil  310  includes windings of electrical wire. The windings of fourth coil  310  are concentric to fourth bar  304 , which corresponds to being wound around first dimension  216  ( FIG. 2A ). 
     Beam control assembly  208  includes a third electrical power supply  312  electrically connected to third coil  308  without being electrically connected to any other coil. Beam control  208  also includes a fourth electrical power supply  314  electrically connected to fourth coil  310  without being electrically connected to any other coil. 
     With reference to  FIG. 3B , in one exemplary embodiment, third coil  308  is fixed to a third position  316  in first dimension  216  on third bar  302 . In this exemplary embodiment, fourth coil  310  is also fixed to third position  316  in first dimension  216  on fourth bar  304 . Fourth coil  310  is located opposite third coil  308  at third position  316  in first dimension  216 . Thus, the portion of ribbon beam  202  adjacent to third position  316  in first dimension  216  can be controlled from both sides of gap  214  using third coil  308  and third electrical power supply  312  and/or fourth coil  310  and fourth electrical power supply  314 . 
     With reference to  FIG. 7 , in another exemplary embodiment, fourth coil  310  can be fixed to a fourth position  702  in first dimension  216  on fourth bar  304 . In this exemplary embodiment, one portion of ribbon beam  202  adjacent to third position  316  in first dimension  216  can be controlled from one side of gap  214  using third coil  308  and third electrical power supply  312 , and another portion of ribbon beam  202  adjacent to fourth position  702  can be controlled from another side of gap  214  using fourth coil  310  and second electrical power supply  314 . 
     With reference to  FIG. 3B , in another exemplary embodiment, third coil  308  is configured to move along third bar  302  to be located at different positions in first dimension  216 . Fourth coil  310  is configured to move along fourth bar  304  to be located at different positions in first dimension  216 . Although not depicted, it should be recognized that third coil  308  and fourth coil  310  can be moved using various devices, including actuators, tracks, and the like. 
     In the exemplary embodiment depicted in  FIG. 3A , first bar  210  and third bar  302  are depicted as extending in first dimension  216  across the entire beam width  204  of ribbon beam  202 . As depicted in  FIGS. 2B and 3B , second bar  212  and fourth bar  304  also extend in first dimension  216  across the entire beam width  204 . Additionally, in this exemplary embodiment, first bar  210 , second bar  212 , third bar  302 , and fourth bar  304  all extend from the same side of beam control assembly  208 . One advantage to this exemplary embodiment is that supply lines, including electrical lines, can be supplied from the same side. 
     With reference to  FIG. 8 , in another exemplary embodiment, first bar  210  and third bar  302  extend in first dimension  216  across only a portion of beam width  204  of ribbon beam  202 . Although not depicted, it should be recognized that second bar  212  and fourth bar  304  also extend in first dimension  216  across only a portion of beam width  204  of ribbon beam  202 . As depicted in  FIG. 8 , in this exemplary embodiment, first bar  210  and third bar  302  can extend from opposite sides of beam control assembly  208 . Similarly, second bar  212  and fourth bar  304  can also extend from opposite sides of beam control assembly  208 . 
     With reference to  FIGS. 3A and 8 , when first coil  222  and third coil  308  are fixed to first position  230  and third position  316 , respectively, on first bar  210  and third bar  302 , respectively, first coil  222  and third coil  308  can be positioned such that the portion of ribbon beam  202  adjacent to first coil  222  overlaps with the portion of ribbon beam  202  adjacent to third coil  308 . In a similar manner, second coil  224  and fourth coil  310  can be positioned such that the portion of ribbon beam  202  adjacent to second coil  224  overlaps with the portion of ribbon beam  202  adjacent to fourth coil  310 . 
     It should be recognized that beam control assembly  208  can include any number of bars located at different positions along second dimension  218 , each bar having only one coil disposed on the bar, with the coils of the different bars located at different positions along first dimension  216 . For example,  FIG. 9  depicts 8 bars located at 8 different positions along second dimension  218 , each bar having only one coil disposed on the bar, with the 8 coils of the 8 different bars located at 8 different positions along first dimension  216  such that the entire beam width  204  of ribbon beam  202  can be controlled separately by the coils. 
     With reference to  FIG. 10 , in one exemplary embodiment, the bars described above (such as first bar  210  in  FIG. 2 ) are steel bars. As depicted in  FIG. 10 , the bars can have a greatest width  1002  of about 50 to 100 mm. It should be recognized, however, that the bars can be made of various types of materials, and have various dimensions. 
     Also, the coils described above (such as first coil  222  in  FIG. 2A ) were described as being windings of electrical wire. In one exemplary embodiment, the coils are copper wires. It should be recognized, however, that the coils can be made of various types of electrically conductive material. 
     Although exemplary embodiments have been described, various modifications can be made without departing from the spirit and/or scope of the present invention. Therefore, the present invention should not be construed as being limited to the specific forms shown in the drawings and described above.