Abstract:
In an embodiment, an ion beam profiler center measuring apparatus is releasably mounted to the ion beam profiler and measures a center position of an ion beam profiler using a laser beam. Accurate data for a profiler center position may be obtained without direct contact with a platen. A procedure to measure and adjust a center position of the ion beam profiler may be easily performed regardless of an operator&#39;s dexterity, requiring relatively little time.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application hereby claims priority under 35 U.S.C. § 119 to Korean Patent Application 2005-70325 filed on Aug. 1, 2005, of which the entire contents are hereby incorporated herein by reference.  
       BACKGROUND  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to an ion implanter, and more particularly, to an apparatus for measuring a position of an ion beam profiler and a method of its use.  
         [0004]     2. Description of the Related Art  
         [0005]     Semiconductor manufacturing generally includes an ion implanting process that implants conductive impurities into a semiconductor wafer. This process uses an ion beam generated by an ion source. In a general ion implanter, impurities are ionized from an ion source, and these impurity ions are then accelerated to form an ion beam having a predetermined energy. The intensity and direction of the accelerated beam are controlled, so that the beam is implanted into the surface of a wafer. At this point, a conductive region corresponding to the energy of the ion beam may be formed in the wafer.  
         [0006]     The energy of an ion contained in a beam is a crucial factor determining a travel depth within a semiconductor wafer before the ion is implanted into the wafer&#39;s semiconductor lattice. Recipes for a given integrated circuit device call for ion implanting using various ion species, energies, and doses. Therefore, when one parameter of an ion beam changes, other parameters in turn change. These changes often require a modification of the ion implanter. Also, preventive maintenance of the ion implanter is important to optimize transmission and transfer of the beam to the wafer.  
         [0007]     Generally, during the set up or preventive maintenance of the ion implanter, an operator measures and examines the position of the center of a beam profiler to set parameters for a predetermined recipe in connection with a new beam profile of an ion implanter, which takes much time. For example, it often takes more than fifteen minutes for an experienced operator to set an ion implanter into an operable state. The ion implanter cannot perform an ion implanting process while the ion implanter is being set, so that equipment downtime occurs.  
         [0008]     A general ion implanter includes an end station. The end station includes a platen for supporting a wafer, a tilt mechanism for tilt adjustments of the platen in X-axis and Y-axis directions, and a measurement system for measuring a parallel state and a direction of a beam. Also, the end station further includes a Faraday beam profiler located adjacent to the platen. The beam profiler allows a scanned ion beam to perform a translational motion parallel to the surface of the wafer. Therefore, uniformity of the scanned ion beam is determined by allowing the beam profiler to perform a translational motion across a plane of the wafer while monitoring a beam current.  
         [0009]     As partly described above, a general ion implanter performs tilt mechanism correction and then senses an angle of an ion beam using a beam profiler and a Faraday cup to adjust the uniformity and direction of the ion beam. However, even when the sensed beam angle is compatible with a standard of a predetermined recipe, equipment tends to drift over time, causing errors that are detected when the beam angle is measured again during a subsequent process. Therefore, the position of the center of the beam profiler needs to be examined after the tilt mechanism correction.  
         [0010]     For example, a high current or medium current ion implanter manufactured by Varian Semiconductor Equipment uses a jig set to measure and examine the center position of a beam profiler during set up (or prevention maintenance) after a tilt mechanism correction.  
         [0011]     The jig set includes a body mounted in a slit provided to a profiler, a pendulum vertically falling to a platen&#39;s lower end that adjusts tilt of the platen through a thread coupled to a hole formed in one end of the body, and a ruler for contacting the platen to measure a distance between the thread and an outer periphery of the platen.  
         [0012]     However, the above-described ion implanter performs platen tilt correction and then examines the center position of a profiler. At this point, because a chamber space of an end station is narrow, it is difficult to mount a jig set and check an exact position of the pendulum. Also, it is difficult to check center data during center examination. Also, since part of the jig set, namely a ruler, may directly contact the platen, there is a high possibility that scratches are generated on the surface of the platen. Also, since the outer periphery of the platen contacting the vertical surface of the ruler is a curved surface, it is difficult to measure exact center data.  
       SUMMARY  
       [0013]     Embodiments provide an apparatus for measuring a center position of a beam profiler in a fast, accurate, and easy manner.  
         [0014]     Embodiments also provide an apparatus for measuring a center of a beam profiler using a laser.  
         [0015]     Embodiments also provide an apparatus for measuring center data of a beam profiler accurately and easily.  
         [0016]     Embodiments also provide an ion implanter and a method thereof using an apparatus for easily measuring a center of a beam profiler.  
         [0017]     In an embodiment, the apparatus for measuring a center of a beam profiler uses a laser. The apparatus for measuring the center of the beam profiler using the laser may measure the center fast and accurately, while preventing scratches on a platen.  
         [0018]     Embodiments provide an apparatus for measuring a center position of a beam profiler for an ion implanter having a platen for supporting a wafer, a tilt mechanism for tilt adjustment of the platen, and the beam profiler for detecting a direction of an ion beam scanned on the wafer, the apparatus including: a body having one end mounted on and separable from the beam profiler; a light-emitting unit provided to the other end of the body, for generating a laser from a lower surface of the light-emitting unit to a center position provided to one side of the tilt mechanism, wherein the lower surface of the light-emitting unit and one side of the tilt mechanism are perpendicular to each other.  
         [0019]     In other embodiments, the light-emitting unit includes: a laser pointer for generating the laser; a housing for mounting the laser pointer therein; a fixing member for fixing and separating the laser pointer in and from the housing; and a switch for electrically switching the laser pointer to generate or cut off the laser, wherein the housing includes a laser hole formed in a center of the lower surface and through which the laser is emitted.  
         [0020]     The switch may include a screw type switch.  
         [0021]     In still other embodiments, the housing further includes a switch fixing part for fixing the switch, and the switch fixing part prevents the switch from being separated from the housing when the switch is turned-off.  
         [0022]     In still other embodiments, the laser pointer includes a light source for generating the laser, a battery for supplying a power source to the light source, and a cap opened to allow the battery to be replaced.  
         [0023]     One side of the tilt mechanism may include a center marking part for marking the center position.  
         [0024]     One side of the tilt mechanism may be one side of a Y-axis tilt driving device of the platen.  
         [0025]     The apparatus may determine a center position of the beam profiler as normal when the laser coincides with the center position.  
         [0026]     Some embodiments provide an ion implanter having a measurement apparatus using a laser. The ion implanter according to the present invention allows position measurement of center data of a beam profiler to be performed fast, accurately, and easily.  
         [0027]     Also, some embodiments provide an ion implanter including: a beam profiler provided to the ion implanter; a platen for loading a wafer; a tilt mechanism for tilt adjustment of the platen; a beam profiler measuring apparatus inserted into and separated from the beam profiler, for generating a laser to one side of the tilt mechanism to measure a center position of the beam profiler; and a controller for horizontally moving the beam profiler and updating data regarding the measured center position as center data of the beam profiler.  
         [0028]     In other embodiments, the beam profiler measuring apparatus includes: a body having one end mounted on and separated from the beam profiler; a light-emitting unit provided to the other end of the body, for generating a laser from a lower surface of the light-emitting unit to a center position provided to one side of the tilt mechanism, wherein the lower surface of the light-emitting unit and one side of the tilt mechanism are perpendicular to each other.  
         [0029]     Embodiments provide a method of measuring a position of a center of a beam profiler using a beam profiler center measuring apparatus for an ion implanter, the method including: moving the beam profiler to a center position of a platen; mounting the beam profiler center measuring apparatus to the beam profiler; turning on a laser pointer of the beam profiler center measuring apparatus to generate a laser to one side of a tilt mechanism; determining whether the generated laser coincides with a center position provided on one side of the tilt mechanism; and regarding a center position of the beam profiler as normal when the laser coincides with the center position provided on one side of the tilt mechanism.  
         [0030]     In other embodiments, the method further includes adjusting a position of the beam profiler when the laser does not coincide with the center position. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0031]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:  
         [0032]      FIG. 1  is a perspective view of a beam profiler center measuring apparatus according to an embodiment;  
         [0033]      FIGS. 2A through 2C  are elevation and plan views of the beam profiler center measuring apparatus illustrated in  FIG. 1 ;  
         [0034]      FIG. 3  is a cross-sectional view of an inner construction of a light-emitting unit of the beam profiler center measuring apparatus illustrated in  FIG. 1 ;  
         [0035]      FIG. 4  is a perspective view of a beam profiler center measuring apparatus according to another embodiment;  
         [0036]      FIG. 5  is a perspective view illustrating part of an ion implanter using a beam profiler center measuring apparatus of  FIG. 1  according to an embodiment;  
         [0037]      FIG. 6  is an elevation view illustrating a state in which a beam profiler center of the ion implanter illustrated in  FIG. 5  is measured; and  
         [0038]      FIG. 7  is a flowchart illustrating a method of adjusting, at an ion implanter, a beam profile center using a beam profiler center measuring apparatus. 
     
    
     DETAILED DESCRIPTION  
       [0039]     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. However, the present invention is not limited to the embodiments illustrated herein after, and the embodiments herein are rather introduced to provide easy and complete understanding of the scope and spirit of the present invention. In the drawings, the shapes of elements are exaggerated for clarity.  
         [0040]      FIG. 1  is a perspective view of a beam profiler center measuring apparatus according to an embodiment, and  FIGS. 2A through 2C  are elevation and plan views of the beam profiler center measuring apparatus illustrated in  FIG. 1 .  
         [0041]     Referring to  FIG. 1 , the beam profiler center measuring apparatus  100  is provided as a jig for measurement, and includes a body  102  that can be mounted on and separated from a beam profiler provided to an end station of an ion implanter, and a light-emitting unit  120  for generating a laser to measure a center position of the beam profiler. Here, the ion implanter is a medium current ion implanter.  
         [0042]     The beam profiler center measuring apparatus  100  (referred to as a jig) allows an adjustment and check of a center position of the beam profiler using a laser, for example, during set up or preventive maintenance (PM) of an ion implanter.  
         [0043]     In detail, referring to  FIGS. 2A through 2C , the jig  100  has an end that can be inserted into an aperture, for instance a hole or slot, of a beam profiler of an end station. The other end is where the light-emitting unit  120  is provided. The body  102  and the light-emitting unit  120  may be integrally formed.  
         [0044]     The light-emitting unit  120  includes a housing  104  in which a laser pointer  110  is mounted, a fixing member  106  for fixing the laser pointer  110  to the housing  104 , and a switch  108  for electrically turning on and off the laser pointer  110 . A laser hole  114 , shown in  FIG. 2C  may be formed in a center of a lower surface of the housing  104  so that a laser beam is emitted to the outside.  
         [0045]     The switch  108  may include a screw type switch, for example, to maintain a switch-on state.  
         [0046]     The laser pointer  110  may be inserted into, or separated from, the housing  104 , which may include a switch fixing part  105  for preventing the switch  108  from being separated from the housing  104  when the switch is turned off.  
         [0047]     The switch fixing part  105  may be integrally formed with the housing  104  to prevent the switch  108  from being separated from the housing  104  when the switch  108  is turned on and off as the switch  108  horizontally rotates.  
         [0048]     The fixing member  106  may be provided as a screw, for example, to allow easy replacement of the laser pointer  110 .  
         [0049]     Referring to  FIG. 3 , a battery (not shown) for supplying power may be mounted in an inside  109  of the laser pointer  110 , which includes a light source  116  for receiving power from the battery and generating a laser, and an electrical circuit (not shown) for connecting the battery, the light source  116 , and the switch  108 . Also, the light source  116  may be located to face the laser hole  114  formed in the center of the lower surface of the laser pointer  110 . That is, a lower surface of the housing  104  and one side of a tilt mechanism are perpendicular to each other, and the laser hole  114  may be formed in the center of the lower surface of the housing  104 , so that a laser is always projected perpendicularly, and thus accurate settings are achieved even when the laser pointer  110  is replaced.  
         [0050]     Also, the laser pointer  110  may include a cap  112  formed on an upper end of the laser pointer  110  to allow replacement of a battery. The cap  112  may be opened to replace a battery (e.g., a mercury battery or a dry battery).  
         [0051]     In other embodiments, a beam profiler center measuring apparatus  100 ′ (jig), shown in  FIG. 4 , is suitable for a high current ion implanter. That is, the jig  100 ′ is a modification in size and shape of the jig  100  and the body  102  of  FIG. 1 . Accordingly, the jig  100 ′ includes the same elements  104  through  120  as those of the jig  100  illustrated in  FIGS. 1 and 2 A- 2 C. Since the elements  104  through  120  have the same functions as those of the elements illustrated in the earlier figures described above, detailed descriptions thereof will be omitted.  
         [0052]     Therefore, since the beam profiler center measuring apparatuses  100  or  100 ′, according to the embodiments, use a laser, and thus do not have a portion directly contacting a platen (or an electrostatic chuck), scratches generated on the platen may be fundamentally prevented. Also, the embodiments reduce time needed for set up or PM by reducing the time needed for measuring center data for a beam profiler.  
         [0053]     A method of measuring a beam profiler center of an ion implanter of a high current or medium current using a jig of the above-described embodiments will now be illustrated.  
         [0054]      FIGS. 5 and 6  are perspective views illustrating part of an ion implanter  200  using a beam profiler center measuring apparatus  100  or  100 ′ according to the embodiments. Here, part of an end station of the ion implanter  200  is illustrated.  
         [0055]     Referring to  FIGS. 5 and 6 , the ion implanter  200  includes a beam profiler  204 , a platen  202  (or an electrostatic chuck) for loading a wafer, and a tilt mechanism  210  for tilt adjustment of the platen  202 . The tilt mechanism  210  includes an X-axis tilt adjustment driving device  212  and a Y-axis tilt adjustment driving device  214 . A center marking part  216  may be provided on one side of the Y-axis tilt adjustment driving device  214 , for example, a surface of the Y-axis tilt adjustment driving device  214  that faces the beam profiler  204 . The center marking part  216  may be located at the axis of rotation of the Y-axis tilt adjustment driving device  214 . Therefore, a laser beam  130  (shown in  FIG. 6 ) generated from a laser pointer of the beam profiler center measuring apparatus  100 ′ mounted in a hole or slot of a beam profiler  204  may reach the center marking part  216  perpendicularly. At this point, when a destination point of the laser  130  coincides with the center marking part  216 , it is determined that the beam profiler  204  is set at a center position.  
         [0056]     However, when the destination point of the laser  130  does not coincide with the center marking part  216 , a driver  206  (or controller) may horizontally move the beam profiler  204  to adjust the center position of the beam profiler  204 . The driver  206  may utilize data, herein referred to as adjusted center data, to make these position adjustments. The adjusted center data of the driver  206  may be updated as needed for subsequent processes.  
         [0057]      FIG. 7  is a flowchart illustrating a method of adjusting, at an ion implanter of the embodiments, a beam profile center using a beam profiler center measuring apparatus. This method is performed during set up or PM of an ion implanter. The method may be performed after tilt adjustment of a platen is completed.  
         [0058]     Referring to  FIG. 7 , in operation S 250 , a beam profiler may be positioned at a center of a platen. In operation S 252 , a beam profiler center measuring apparatus may be installed in a hole or slot of the beam profiler. In operation S 254 , a laser pointer may be turned on to emit a laser beam to one side of a tilt mechanism, and may be parallel to a surface of the platen or the surface of the mounted wafer. The laser may be emitted perpendicularly toward a center marking part provided on one side of the tilt mechanism to correspond to a center position of the platen. That is, since a laser hole may be provided perpendicularly to one side of the tilt mechanism, the laser may always be perpendicularly emitted to one side of the tilt mechanism.  
         [0059]     In operation S 256 , whether the emitted laser beam coincides with the center marking part provided on one side of the tilt mechanism may be determined. When the laser beam coincides with the center marking part as a result of the determination, operation S 260  may be performed to determine if a position of the profiler center is normal. However, when the laser beam does not coincide with the center marking part as a result of the determination, operation S 258  may be performed to adjust the position of the profiler, and then operation S 256  may thereafter be performed. While adjusting the position of the profiler, the laser beam may be “swept” through a plane that is parallel to the surface of the platen or mounted wafer, until the laser beam position is adjusted to coincide with the center marking part, for example.  
         [0060]     As described above, the ion implanter according to the embodiments uses a laser to measure a center of a beam profiler. The measuring apparatus is simple, allowing work efficiency to improve. For example, a conventional process of measuring a center of a beam profiler may take about fifteen minutes, while the time taken for measuring a center of a beam profiler is about two minutes according to the embodiments. Also, the measuring apparatus may be operated by an operator according to a manual (e.g., standard operation procedure (SOP) or a one-point lesson sheet (OPLS)) regardless of the operator&#39;s dexterity. Modifications of the measuring apparatus are made in size and shape to be compatible with a variety of ion implanters, so that the measuring apparatus may be applied to ion implanters of a high current and of a medium current.  
         [0061]     It will be apparent to those skilled in the art that various modifications and variations can be made in the embodiments. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.