Patent Publication Number: US-2015060433-A1

Title: High temperature platen power contact

Description:
FIELD OF THE DISCLOSURE 
     Embodiments of the present disclosure generally relate to the field of substrate processing, and more particularly to high temperature platens and power contacts used to support a substrate during semiconductor device manufacturing. 
     BACKGROUND OF THE DISCLOSURE 
     Ion implantation is a process of depositing chemical species into a substrate by direct bombardment of the substrate with energized ions. In semiconductor manufacturing, ion implanters are used primarily for doping processes that alter the type and level of conductivity of target materials. A precise doping profile in an integrated circuit (IC) substrate and its thin-film structure is important for proper IC performance. To achieve a desired doping profile, one or more ion species may be implanted in different doses and at different energies. 
     In some ion implantations processes, the desired doping profile is achieved by implanting ions in the target substrate at high temperatures (e.g., between 150-600° Celsius.) Heating the target substrate can be achieved by supporting the substrate on a heated platen during the ion implant process. A typical heated platen may include one or more heating elements connected to a power source via electrical contacts. During operation, these electrical contacts are subjected to stresses associated with high temperature operation. In addition, these electrical contacts may absorb some of the heat from the heating element, effectively acting as small heat sinks that can reduce the temperature of the heated platen in areas adjacent to the electrical contacts. As will be appreciated, any temperature variation between portions of the heated platen may be affect the uniformity of the heat transferred to the target substrate. As a result, the target substrate may have sections that are heated to different temperatures, which may adversely affect the ion implantation process. In some instances, the heated platen can warp or bow as it is heated, and it would be desirable to provide electrical contacts that can provide consistent electrical contact with a power source even when the heated platen is not completely flat. 
     In view of the foregoing, it will be understood that there is a need to ensure that electrical contacts for heated platens operate sufficiently at high temperatures, have low thermal conductivity, and maintain electrical contact throughout out a range of operating temperatures. 
     SUMMARY 
     This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended as an aid in determining the scope of the claimed subject matter. 
     In general, various embodiments of the present disclosure provide an electrical connection assembly for use in a heated platen having a dielectric plate with a heating element and a terminal electrically connected to the heating element disposed therein. The assembly can include an electrical connection plug, and a connector pin having a bottom portion and a top portion. The bottom portion can be configured for electrically coupling to the electrical connection plug. The top portion can have a spring structure configured to maintain electric contact with the terminal of the heated platen by biasing the top portion against the terminal. 
     Some embodiments disclose an electrical connection assembly for use in a heated platen having a dielectric plate with a heating element and a terminal electrically connected to the heating element disposed therein. The assembly may include an electrical connection plug, a conductive sleeve disposed within the electrical connection plug, and a connector pin having a bottom portion and a top portion. The bottom portion may be disposed within the conductive sleeve. The top portion may have a spring structure. The spring structure may be configured to maintain electric contact with the terminal throughout a range of temperatures. 
     Some embodiments include a heated platen comprising a dielectric plate having a heating element and a terminal disposed therein. The terminal may provide electrical contact to the heating element. An electrical connection assembly may be configured to connect the heating element to a power source. The electrical connection assembly may include an electrical connection plug, a conductive sleeve disposed within the electrical connection plug, and a connector pin having a bottom portion and a top portion. The bottom portion may be disposed within the sleeve. The top portion may have a spring structure. The spring structure may be configured to maintain electric contact with the terminal throughout a range of temperatures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       By way of example, various embodiments of the disclosed device will now be described, with reference to the accompanying drawings, in which: 
         FIGS. 1A-1B  are block diagrams of an exemplary substrate support platen; 
         FIG. 2  is a block diagram of a portion of an exemplary heated platen; 
         FIG. 3  is a block diagram of a portion of another exemplary heated platen; 
         FIG. 4  is a block diagram of a portion of a further exemplary heated platen; 
         FIGS. 5A-5C  are isometric, and first and second side view of an exemplary connector pin for use with a heated platen according to one or more embodiments of the disclosure; 
         FIG. 6  is a block diagram of another exemplary connector pin for use with a heated platen according to one or more embodiments of the disclosure; and 
         FIGS. 7A and 7B  are isometric and side views, respectively, of a further exemplary connector pin for use with a heated platen according to one or more embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure provide for electrical contact between a power source and a heated platen. During operation, as the temperature of the heated platen is increased, the electrical contacts described herein may provide for robust operation at the high operating temperatures. Furthermore, the electrical contacts described herein may have a relatively low thermal conductivity, so that a minimum amount of heat from the heated platen may be absorbed by the electrical contacts. As will be appreciated, the electrical contacts described herein may be implemented in a heated platen which may be used to support a substrate during processing. For example, the heated platen may be used to support a substrate during an ion implant process, a plasma deposition process, an etching process, a chemical mechanical planarization process, or generally any process where a semiconductor substrate is to be supported on a heated platen. As such, an example heated platen is described. It will be appreciated however, that the embodiments of the present disclosure are not limited by the described example heated platen and may find application in any of a variety of platen applications used in a variety of semiconductor manufacturing processes. 
       FIG. 1A  illustrates a block diagram showing a cut-away view of a heated platen  122 . As depicted, the heated platen  122  may be coupled to a scanner mechanism  124  that facilitates various angular and/or rotational movements of the platen  122 . The platen  122  may comprise a dielectric plate  130  and an interface plate  126 . The dielectric plate  130  may have electrodes  132  embedded therein to apply an electrostatic force to hold the substrate  120  onto a surface of the dielectric plate  130 . The surface of the dielectric plate  130  may either be smooth or it may contain mesa structures  134  to reduce backside contact to the substrate  120  and to reduce the generation of backside particles. One or more interface regions  136  may be formed between the substrate  120  and the dielectric plate  130 . These interface regions may, in some embodiments, contain a backside gas to improve or adjust thermal contact between the substrate  120  and the dielectric plate  130 . 
     One or more heating elements  138  may be embedded in the dielectric plate  130  to heat the dielectric plate  130  and to maintain the heated platen  122  at a desired temperature or within a desired temperature range. In some embodiments the heating elements may comprise an electrically conductive material. During operation, to heat the substrate  120  the heating elements  138  may be activated, as will be described in greater detail below. In some examples, the heating elements  138  may be configured to heat the dielectric layer  130  to a temperature of between 150 and 600° C. In some embodiments the interface plate  126  may include cooling passages  128 , through which a cooling fluid may be passed to cool the heated platen  122  back down to, or below, room temperature. 
       FIG. 1B  illustrates a block diagram showing a top view of the dielectric plate  130 . As depicted, the dielectric plate  130  includes heating elements  138   a  and  138   b.  As noted above, the dielectric plate  130  also includes electrodes  132  configured to hold the substrate  120  on the dielectric plate  130  via static electricity. These electrodes  132  are not shown in  FIG. 1B  for clarity. Furthermore, although the dielectric plate  130  is shown having two heating elements (e.g.,  138   a  and  138   b ,) it will be appreciated that in practice, the dielectric plate  130  may have greater or fewer heating elements, as desired. The heating elements  138   a,    138   b  include terminals  140   a,    142   a  and  140   b,    142   b  respectively. During operation, electric current may be passed through the heating elements  138   a,    138   b  by applying a voltage potential to the terminals  140   a,    142   a  and  140   b,    142   b.  As a result of the current passing through the heating elements  138   a,    138   b,  the temperature of the heating elements will increase. This temperature increase may be thermally conducted through the dielectric plate  130  to the substrate  120 . In some examples, the dielectric plate  130  may be formed from a ceramic material having a low dielectric constant. The heating elements  138   a,    138   b  may be formed from a thick film paste, such as, for example, silver palladium. 
       FIG. 2  illustrates a block diagram showing a cutaway view of a portion of an exemplary heated platen  200 . The heated platen  200  of this embodiment may be the same as or similar to the heated platen  122  described in relation to  FIGS. 1A-1B . As depicted, the heated platen  200  includes a dielectric plate  202  having a heating element  204  and a corresponding terminal  206  disposed therein. The dielectric plate  202  is disposed on an interface plate  208 . An electrical contact assembly  210  is disposed within the interface plate  208  and provides electrical connection between a power supply (via electrical connection plug  220 ) and the terminal  206 . It is to be appreciated that  FIG. 2  illustrates only a portion of the heated platen  200 . More specifically, only a single terminal (i.e., terminal  206 ) is shown. It will be appreciated that the heated platen  200  will also include a second terminal and a corresponding electrical contact assembly (both not shown for purposes of clarity) to complete a heating circuit between the terminals. Furthermore, the heated platen  200  may include additional heating element(s), corresponding terminals and electrical contact assemblies, to achieve a desired heating capacity for the heated platen  200 . It will also be appreciated that the heated platen  200  may include electrodes, for example, which can be used to electrostatically clamp a substrate to the heated platen in the manner described above with respect to  FIG. 1B . Such electrodes are also not shown in the current view for purposes of clarity. 
     As depicted, the electrical contact assembly  210  includes a connector pin  212 , a conductive sleeve  214 , a banana clip  216 , a nonconductive sleeve  218 , an electrical connection plug  220  and an O-ring  222 . In general, the electrical contact assembly  210  is arranged to allow the conduction of electric current from the electrical connection plug  220  to the connector pin  212  and the terminal  206 . The current may be conducted from the electrical connection plug  220  through the conductive sleeve  214 , the banana clip  216  and the connector pin  212 . The connector pin  212  may have various geometries, which will be described in greater detail below. The nonconductive sleeve  218  may be formed from a material having high dielectric properties (e.g., alumina, or the like,) in order to prevent or suppress arcing. The O-ring  222  may be provided to seal the electrical connection plug  220  to the interface plate  208 . As depicted, the O-ring  222  may fit within a recess formed in the interface plate  208 . 
       FIG. 3  illustrates a block diagram showing a cut-away view of another example heated platen  300 . The heated platen  300  of this embodiment may be the same or similar to the heated platens previously described in relation to  FIGS. 1A-2 . As depicted, the heated platen  300  includes a dielectric plate  302  having a heating element  304  and a corresponding terminal  306  disposed therein. The dielectric plate  302  is disposed on an interface plate  308 . An electrical contact assembly  310  is disposed within the interface plate  308  and provides electrical connection to the terminal  306 . It will be appreciated, that  FIG. 3  illustrates only a portion of the heated platen  300 . More specifically, only a single terminal (i.e., terminal  306 ) is shown. It will be appreciated that heated platen  300  will include a second terminal and a corresponding electrical contact assembly (both not shown for purposes of clarity). Furthermore, the heated platen  300  may include additional heating element(s), corresponding terminals and electrical contact assemblies to provide a desired heating capacity to the heated platen. It will also be appreciated that the heated platen  300  may include electrodes, for example, which can be used to electrostatically clamp a substrate to the heated platen in the manner described above with respect to  FIG. 1B . Such electrodes are also not shown in the current view for purposes of clarity. 
     As depicted, the electrical contact assembly  310  includes a connector pin  312 , a non-conductive sleeve  314 , a connection plug  316  and a plurality of O-rings  318  for sealing the elements of the electrical contact assembly together and to the interface plate  308 . As can be seen, the non-conductive sleeve  314  surrounds the connector pin  312  along and extends upward toward the terminal  306 , thus forming an insulating sleeve around the connector pin  312  to prevent arcing during operation. In general, the electrical contact assembly  310  is arranged to allow the conduction of electric current to the terminal  306  through the connector pin  312 . In some applications, current may be conducted from the connection plug  316  directly to the connector pin  312 . In such embodiments, a layer of dielectric or other insulating material may be provided between the connection plug  316  and the interface plate  308 . In some embodiments, the connection plug  316  is non-conductive. In such applications, the connector pin  312  may be connected to a current source via the bottom portion  313  of the connector pin. In further applications, the non-conductive element  314  and the connection plug  316  may be formed from the same non-conductive material (e.g., ceramic, dielectric, or the like) and even may be formed as a single component. 
     The connector pin  312  may have various geometries, which will be described in greater detail below. The O-rings  318  may be provided to seal the electrical connection plug  316  to the interface plate  308 , seal the non-conductive sleeve  314  to the electrical connection plug  316  and seal the connector pin  312  to the non-conductive sleeve  314 . As depicted, the plurality of O-rings  318  may fit within corresponding recesses in the interface plate  308  and the various components of the electrical contact assembly. In some embodiments, the non-conductive sleeve  314  may be affixed (e.g., crimped, soldered, welded, bonded, or the like) to the bottom portion  313  of the connector pin  312 . In such cases the O-ring  318  between the two pieces may be eliminated. 
       FIG. 4  illustrates a block diagram showing a cut-away view of another example heated platen  400 . As depicted, the heated platen  400  includes a dielectric plate  402  having a first heating element  404   a  and a second heating element  404   b,  as well as corresponding terminals  406   a  and  406   b  disposed therein. The dielectric plate  402  is disposed on an interface plate  408 . First and second electrical contact assemblies  410   a  and  410   b  are disposed within the interface plate  408  and configured to provide electrical connection to the terminals  406   a  and  406   b  respectively. It is to be appreciated that  FIG. 4  illustrates only a portion of the heated platen  400 . More specifically, only one terminal (i.e., the terminal  406   a  or  406   b ) for either of the heating elements  404   a  or  404   b  is shown. It will be appreciated that the heated platen  400  will include a second terminal and a corresponding electrical contact assembly for each of the heating elements  404   a  and  404   b,  which are not shown for purposes of clarity. Furthermore, the heated platen  400  may include additional heating element(s) and corresponding terminals and electrical contact assemblies. It will also be appreciated that the heated platen  400  may include electrodes, for example, which can be used to electrostatically clamp a substrate to the heated platen in the manner described above with respect to  FIG. 1B . Such electrodes are also not shown in the current view for purposes of clarity. 
     As depicted, the electrical contact assemblies  410   a  and  410   b  each include a connector pin  412   a, b , non-conductive sleeves  414   a, b , and O-rings  416   a, b . More specifically, the electrical contact assembly  410   a  includes the connector pin  412   a,  the non-conductive sleeve  414   a  and the O-rings  416   a.  Similarly, the electrical contact assembly  410   b  includes the connector pin  412   b,  the non-conductive sleeve  414   b  and the O-rings  416   b.  The electrical contact assemblies  410   a  and  410   b  share a single electrical connection plug  418 , which can be fit into the interface plate  408  and sealed with an O-ring  420 . In general, the electrical contact assemblies  410   a,    410   b  are arranged to allow the conduction of electric current from the connection plug  418  to the connector pins  412   a,    412   b  and the terminals  406   a,    406   b.  In some embodiments, current may be conducted from the connection plug  418  directly to the connector pins  412   a,    412   b.  In such applications, a layer of dielectric or other insulating material may be provided between the connection plug  418  and the interface plate  408 . In some embodiments, the connection plug  418  may also be non-conductive. In such applications, the connector pins  412   a,    412   b  may be connected to a current source via their respective bottom portions  413   a,    413   b.  In further applications, the non-conductive elements  414   a,    414   b  and the electrical connection plug  418  may be formed from the same non-conductive material (e.g., ceramic, or the like) and even may be formed as a single component. 
     The connector pins  412   a,    412   b  may have various geometries, which will be described in greater detail below. The O-ring  420  may be provided to seal the electrical connection plug  418  to the interface plate  408 . Similarly, the O-rings  416   a,    416   b  may be provided to seal the non-conductive sleeves  414   a,    414   b  to the electrical connection plug  418  and to seal the connector pins  412   a,    412   b  to the non-conductive sleeves  414   a,    414   b . As depicted, the O-rings  416   a,    416   b,  and  420  may fit within recesses formed in the interface plate  408  and the various components of the electrical contact assemblies. In some exemplary embodiments, the non-conductive sleeves  414   a,    414   b  may be affixed (e.g., crimped, soldered, welded, bonded, or the like) to the bottom portions  413   a,    413   b  of the connector pins  412   a,    412   b.  In such cases, the O-rings  416   a,    416   b  between these pieces may be eliminated. 
       FIGS. 5A-5C ,  FIG. 6 , and  FIGS. 7A-7B  illustrate various exemplary connector pins that can be used with in the heated platens  122 ,  200 ,  300 ,  400  described above. More specifically, various geometries and arrangements of exemplary connector pins are described for operating at high temperatures. Such connector pins have low thermal conductivity and can maintain electrical contact with associated electrical terminals of the heated platen throughout out a range of operating temperatures are described below. 
     Referring now to  FIGS. 5A-5C , various views of an exemplary connector pin  500  are shown. As can be seen, the connector pin  500  includes generally cylindrical bottom and top portions  510 ,  520 . In the illustrated embodiment, the top portion  520  has an outside diameter that is larger than the outside diameter of the bottom portion. The bottom portion  510  may be a solid cylindrical element having a diameter sized to be received within the electrical connection assemblies depicted in either of  FIGS. 2-4 . For example, the bottom portion  510  may have a diameter such that the banana clip  216  ( FIG. 2 ) may make electrical connection with the connector pin  500  and retain the connector pin  500  in the electrical connection assembly. Alternatively, the bottom portion  510  may have a diameter such that it may be received within the annular opening in the conductive sleeve  314  of  FIG. 3  or the conductive sleeves  414   a,    414   b  of  FIG. 4 . In other embodiments, the diameter of the bottom portion  510  may be sized so that the conductive sleeves  314 ,  414   a,  or  414   b  may be crimped around the bottom portion  510  and therefore attached to the connector pin  500 . It will be appreciated that the bottom portion  510  needn&#39;t be cylindrical, but could have other geometric shapes. 
     The top portion  520  of the connector pin  500  may include a spring structure  522  and an electrical contact surface  524 . In the illustrated embodiment, the spring structure  522  is connected at one end to the bottom portion  510  of the connector pin  500 , while the electrical contact surface  524  is disposed at an opposite end of the spring structure. The connector pin  500  may have a length “L” while the spring structure  522  may have a spring length “SL.” In the illustrated embodiment, the spring structure  522  runs the length of the top portion  520 . It will be appreciated, the top portion  520  can include a non-spring portion, the length of which may be adjusted to provide a desired basing force, as will be described below. 
     In general, the spring structure  522  may take the form of a compression spring so that the spring structure can be biased to maintain electrical contact between a terminal (e.g., the terminals  206 ,  306 ,  406   a,  or  406   b ) and the electrical contact surface  524  over a range of operating temperatures. In some non-limiting exemplary embodiments, the range of operating temperatures is 150 to 600° C. And because during operation the dielectric plate  130  may warp and bow as its temperature moves through the range of operating temperatures, the connector pin  500  can be configured to maintain electrical contact between the electrical contact surface  524  and an associated terminal as the dielectric plate warps or bows. In some examples, the spring structure  522  may have a preload force of between approximately 5 and 25 Newtons. In some examples, the spring structure  522  may have a preload force of approximately 10 Newtons. 
       FIG. 5B  shows a first side view of the connector pin  500 , including bottom portion  510 , spring structure  522  and the electrical contact surface  524 .  FIG. 5C  shows a second side view of the connector pin  500  rotated 90-degrees with respect to the side view of  FIG. 5B . As can be seen, the spring structure  522  includes a plurality of leaves  526  that are spaced apart from immediately adjacent leaves by a gap “g.” The plurality of leaves  526  are connected to adjacent leaves via bridge elements  527  disposed, in alternating fashion, on opposite sides of the spring structure. By positioning the bridge elements  527  in this alternating arrangement the spring structure is provided an accordion shape. 
     Some or all of the bridge elements  527  may include central and/or peripheral cutouts  529 ,  531 . These cutouts  529 ,  531  can serve to control heat transfer through the spring structure  522  while also providing the spring structure with a desired biasing force. 
     In some embodiments the connector pin  500  may be formed from a single piece of material. In some examples, the plurality of alternating leaves  526 , bridge elements  527  and cutouts  529 ,  531  may be formed by CNC machining, wire EDM, or other appropriate techniques. 
     The material may be selected such that the electrical resistance is minimized while the flexural modulus and the thermal conductivity is maximized. Specifically, the material may be selected such that these properties are within desired ranges at the desired operating temperature of the spring connector pin  500 . For example, if the connector pin  500  is designed to be operated at 500° C., then the material may be selected such that the flexular modulus, thermal conductivity and resistivity is as desired at 500° C. In some examples, the connector pin  500  may be formed from tungsten, molybdenum, Inconel, titanium or combinations thereof. 
       FIG. 6  illustrates a block diagram showing a further exemplary connector pin  600 . In general, the connector pin  600  may have a shape, structure and configuration similar to the connector pins described in relation to  FIGS. 5A-5C . For example, the connector pin  600  may include a bottom portion  610  and a top portion  620  including a spring structure  622  formed from a plurality of alternating leaves  626 . The electrical contact surface  624  of the connector pin  600 , however, is domed, as opposed to being generally flat like that depicted in  FIGS. 5A-5C . Thus, the electrical contact surface  624  may have a radius of curvature “R,” which in some embodiments may be about 1-inch. Furthermore, the electrical contact surface  624  may be generally convex (as depicted) for the purpose of increasing the area where the electrical contact surface  624  meets the terminal (e.g., the terminals  206 ,  306 ,  406   a,  or  406   b ) of the heated platen. More particularly, the generally convex shaped electrical contact surface  624  may operate to concentrate the point of electrical contact in one region in order to create a more robust electrical path. 
       FIGS. 7A-7B  illustrate various views of an additional exemplary connector pin  700 . As can be seen, the connector pin  700  includes generally cylindrical bottom and top portions  710 ,  720 . In the illustrated embodiment, the top portion  720  has an outside diameter that is larger than the outside diameter of the bottom portion. The bottom portion  710  may have a diameter sized to be received by the electrical connection assemblies depicted in either of  FIGS. 2-4 . For example, the bottom portion  710  may have a diameter such that the banana clips  216  ( FIG. 2 ) may make electrical connection with the connector pin  700  and retain the connector pin  700  in the electrical connection assembly. Alternatively, the bottom portion  710  may have a diameter such that it may be inserted into the annular opening in the conductive sleeve  314  of  FIG. 3  or the conductive sleeves  414   a,    414   b  of  FIG. 4 . Furthermore, the diameter may be such that the conductive sleeves  314 ,  414   a,  or  414   b  may be crimped around the bottom portion  710  and therefore attached to the connector pin  700 . It will be appreciated that the bottom portion  710  needn&#39;t be cylindrical, but could have other geometric shapes. 
     The top portion  720  of the connector pin  700  may include a spring structure  722 , and an electrical contact surface  724  disposed at an end of the top portion  720  opposite the bottom portion  710 . The spring structure  722  may take the form of a helical coil spring, including a plurality of coil elements  725  separated by spaces  727 . The top portion  720  may have a central opening  721  therein, such that the electrical contact surface  724  is generally ring-shaped. Although not shown, it is contemplated that a capped contact surface could be provided (e.g., using an integral or separate cap member) to provide a solid flat or a solid convex contact surface without an opening, or with a reduced size opening. 
     The connector pin  700  may have an overall length “L,” and the spring structure  722  may have a spring length “SL.” In the illustrated embodiment, the top portion  720  includes a non-spring portion  723  disposed between the spring structure  722  and the bottom portion  710 . As will be appreciated, the spring length “SL,” along with other geometric aspects of the spring structure  722  can be adjusted to provide a desired biasing force as will be described below. 
     As with previous embodiments, the spring structure  722  may be biased to maintain electrical contact between a terminal (e.g., the terminals  206 ,  306 ,  406   a,  or  406   b ) and the electrical contact surface  724  over a range of operating temperatures. In some examples, the range of operating temperatures is 150 to 600° C. Because the dielectric plate  130  may warp and bow as its temperature moves through the range of operating temperatures, the connector pin  700  can maintain electrical contact with the terminal as the dielectric plate warps or bows. In some examples, the spring structure  722  may have a biasing force of between approximately 5 and 25 Newtons. In some examples, the spring structure  722  may have a biasing force of approximately 10 Newtons. 
     As noted, the desired biasing force can be obtained by adjusting various of the geometric attributes of the spring structure  722 , including the spring length “SL,” the diameter of the opening  721  and the thickness “T” of the coil elements  725 . Although the illustrated embodiment shows the coil elements  725  being of substantially equal thickness “T,” it will be appreciated that the coil elements  725  can have different thicknesses. In addition, the opening  721  is shown as being substantially cylindrical, however, it could have a varied cross-sectional shape (e.g., tapered) to provide the spring structure  722  (and resulting connector pin  700 ) with a desired biasing characteristic. 
     In some embodiments, the connector pin  700  may be formed from a single piece of material. The material may be selected such that the electrical resistance is minimized while the flexural modulus and the thermal conductivity is maximized. In particular, the material may be selected such that these properties are within desired ranges at a desired operating temperature of the connector pin  700 . For example, if the connector pin  700  is designed to be operated at 500° C., then the material may be selected such that the flexular modulus, thermal conductivity and resistivity is as desired at 500° C. In some examples, the connector pin  700  may be formed from tungsten, molybdenum, Inconel, titanium or combinations thereof. In one embodiment the connector pin  700  is formed from a TZM (titanium-zinc-molybdenum) alloy. 
       FIG. 7B  is a side view of the connector pin  700 . As depicted, the spring structure  722  includes a number of helical coils  726 . In some examples, the helical coils  726  may be formed by cutting helical grooves in the top portion  720  using, for example, CNC machining, wire EDM, or other machining techniques, followed (or alternatively, preceded by) by drilling a hole in the center of the top portion, as depicted in  FIG. 7A . 
     It is to be appreciated, that the methods of forming the connector pins  500 ,  600 , and  700  described above are provided for illustrative purposes only and are not intended to be limiting. Furthermore, the present disclosure is not to be limited in scope by the specific embodiments described herein. Indeed, other various embodiments of and modifications to the present disclosure, in addition to those described herein, will be apparent to those of ordinary skill in the art from the foregoing description and accompanying drawings. Thus, such other embodiments and modifications are intended to fall within the scope of the present disclosure. Furthermore, although the present disclosure has been described herein in the context of a particular implementation in a particular environment for a particular purpose, those of ordinary skill in the art will recognize that its usefulness is not limited thereto and that the present disclosure may be beneficially implemented in any number of environments for any number of purposes. Accordingly, the claims set forth below should be construed in view of the full breadth and spirit of the present disclosure as described herein.