HIGH TEMPERATURE PLATEN POWER CONTACT

A heated platen having a heating element and an electrical contact assembly for the heating element is generally described. Various examples provide a dielectric plate including a heating element and a terminal disposed therein. An electrical connection assembly configured to connect the heating element to a power source is also provided. The electrical connection including 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 disposed within the sleeve, the top portion having a spring structure, the spring structure configured to maintain electric contact with the terminal throughout a range of temperatures.

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

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.

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. 1Aillustrates a block diagram showing a cut-away view of a heated platen122. As depicted, the heated platen122may be coupled to a scanner mechanism124that facilitates various angular and/or rotational movements of the platen122. The platen122may comprise a dielectric plate130and an interface plate126. The dielectric plate130may have electrodes132embedded therein to apply an electrostatic force to hold the substrate120onto a surface of the dielectric plate130. The surface of the dielectric plate130may either be smooth or it may contain mesa structures134to reduce backside contact to the substrate120and to reduce the generation of backside particles. One or more interface regions136may be formed between the substrate120and the dielectric plate130. These interface regions may, in some embodiments, contain a backside gas to improve or adjust thermal contact between the substrate120and the dielectric plate130.

One or more heating elements138may be embedded in the dielectric plate130to heat the dielectric plate130and to maintain the heated platen122at 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 substrate120the heating elements138may be activated, as will be described in greater detail below. In some examples, the heating elements138may be configured to heat the dielectric layer130to a temperature of between 150 and 600° C. In some embodiments the interface plate126may include cooling passages128, through which a cooling fluid may be passed to cool the heated platen122back down to, or below, room temperature.

FIG. 1Billustrates a block diagram showing a top view of the dielectric plate130. As depicted, the dielectric plate130includes heating elements138aand138b.As noted above, the dielectric plate130also includes electrodes132configured to hold the substrate120on the dielectric plate130via static electricity. These electrodes132are not shown inFIG. 1Bfor clarity. Furthermore, although the dielectric plate130is shown having two heating elements (e.g.,138aand138b,) it will be appreciated that in practice, the dielectric plate130may have greater or fewer heating elements, as desired. The heating elements138a,138binclude terminals140a,142aand140b,142brespectively. During operation, electric current may be passed through the heating elements138a,138bby applying a voltage potential to the terminals140a,142aand140b,142b.As a result of the current passing through the heating elements138a,138b,the temperature of the heating elements will increase. This temperature increase may be thermally conducted through the dielectric plate130to the substrate120. In some examples, the dielectric plate130may be formed from a ceramic material having a low dielectric constant. The heating elements138a,138bmay be formed from a thick film paste, such as, for example, silver palladium.

FIG. 2illustrates a block diagram showing a cutaway view of a portion of an exemplary heated platen200. The heated platen200of this embodiment may be the same as or similar to the heated platen122described in relation toFIGS. 1A-1B. As depicted, the heated platen200includes a dielectric plate202having a heating element204and a corresponding terminal206disposed therein. The dielectric plate202is disposed on an interface plate208. An electrical contact assembly210is disposed within the interface plate208and provides electrical connection between a power supply (via electrical connection plug220) and the terminal206. It is to be appreciated thatFIG. 2illustrates only a portion of the heated platen200. More specifically, only a single terminal (i.e., terminal206) is shown. It will be appreciated that the heated platen200will 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 platen200may include additional heating element(s), corresponding terminals and electrical contact assemblies, to achieve a desired heating capacity for the heated platen200. It will also be appreciated that the heated platen200may include electrodes, for example, which can be used to electrostatically clamp a substrate to the heated platen in the manner described above with respect toFIG. 1B. Such electrodes are also not shown in the current view for purposes of clarity.

As depicted, the electrical contact assembly210includes a connector pin212, a conductive sleeve214, a banana clip216, a nonconductive sleeve218, an electrical connection plug220and an O-ring222. In general, the electrical contact assembly210is arranged to allow the conduction of electric current from the electrical connection plug220to the connector pin212and the terminal206. The current may be conducted from the electrical connection plug220through the conductive sleeve214, the banana clip216and the connector pin212. The connector pin212may have various geometries, which will be described in greater detail below. The nonconductive sleeve218may be formed from a material having high dielectric properties (e.g., alumina, or the like,) in order to prevent or suppress arcing. The O-ring222may be provided to seal the electrical connection plug220to the interface plate208. As depicted, the O-ring222may fit within a recess formed in the interface plate208.

FIG. 3illustrates a block diagram showing a cut-away view of another example heated platen300. The heated platen300of this embodiment may be the same or similar to the heated platens previously described in relation toFIGS. 1A-2. As depicted, the heated platen300includes a dielectric plate302having a heating element304and a corresponding terminal306disposed therein. The dielectric plate302is disposed on an interface plate308. An electrical contact assembly310is disposed within the interface plate308and provides electrical connection to the terminal306. It will be appreciated, thatFIG. 3illustrates only a portion of the heated platen300. More specifically, only a single terminal (i.e., terminal306) is shown. It will be appreciated that heated platen300will include a second terminal and a corresponding electrical contact assembly (both not shown for purposes of clarity). Furthermore, the heated platen300may 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 platen300may include electrodes, for example, which can be used to electrostatically clamp a substrate to the heated platen in the manner described above with respect toFIG. 1B. Such electrodes are also not shown in the current view for purposes of clarity.

As depicted, the electrical contact assembly310includes a connector pin312, a non-conductive sleeve314, a connection plug316and a plurality of O-rings318for sealing the elements of the electrical contact assembly together and to the interface plate308. As can be seen, the non-conductive sleeve314surrounds the connector pin312along and extends upward toward the terminal306, thus forming an insulating sleeve around the connector pin312to prevent arcing during operation. In general, the electrical contact assembly310is arranged to allow the conduction of electric current to the terminal306through the connector pin312. In some applications, current may be conducted from the connection plug316directly to the connector pin312. In such embodiments, a layer of dielectric or other insulating material may be provided between the connection plug316and the interface plate308. In some embodiments, the connection plug316is non-conductive. In such applications, the connector pin312may be connected to a current source via the bottom portion313of the connector pin. In further applications, the non-conductive element314and the connection plug316may 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 pin312may have various geometries, which will be described in greater detail below. The O-rings318may be provided to seal the electrical connection plug316to the interface plate308, seal the non-conductive sleeve314to the electrical connection plug316and seal the connector pin312to the non-conductive sleeve314. As depicted, the plurality of O-rings318may fit within corresponding recesses in the interface plate308and the various components of the electrical contact assembly. In some embodiments, the non-conductive sleeve314may be affixed (e.g., crimped, soldered, welded, bonded, or the like) to the bottom portion313of the connector pin312. In such cases the O-ring318between the two pieces may be eliminated.

FIG. 4illustrates a block diagram showing a cut-away view of another example heated platen400. As depicted, the heated platen400includes a dielectric plate402having a first heating element404aand a second heating element404b,as well as corresponding terminals406aand406bdisposed therein. The dielectric plate402is disposed on an interface plate408. First and second electrical contact assemblies410aand410bare disposed within the interface plate408and configured to provide electrical connection to the terminals406aand406brespectively. It is to be appreciated thatFIG. 4illustrates only a portion of the heated platen400. More specifically, only one terminal (i.e., the terminal406aor406b) for either of the heating elements404aor404bis shown. It will be appreciated that the heated platen400will include a second terminal and a corresponding electrical contact assembly for each of the heating elements404aand404b,which are not shown for purposes of clarity. Furthermore, the heated platen400may include additional heating element(s) and corresponding terminals and electrical contact assemblies. It will also be appreciated that the heated platen400may include electrodes, for example, which can be used to electrostatically clamp a substrate to the heated platen in the manner described above with respect toFIG. 1B. Such electrodes are also not shown in the current view for purposes of clarity.

As depicted, the electrical contact assemblies410aand410beach include a connector pin412a, b, non-conductive sleeves414a, b, and O-rings416a, b. More specifically, the electrical contact assembly410aincludes the connector pin412a,the non-conductive sleeve414aand the O-rings416a.Similarly, the electrical contact assembly410bincludes the connector pin412b,the non-conductive sleeve414band the O-rings416b.The electrical contact assemblies410aand410bshare a single electrical connection plug418, which can be fit into the interface plate408and sealed with an O-ring420. In general, the electrical contact assemblies410a,410bare arranged to allow the conduction of electric current from the connection plug418to the connector pins412a,412band the terminals406a,406b.In some embodiments, current may be conducted from the connection plug418directly to the connector pins412a,412b.In such applications, a layer of dielectric or other insulating material may be provided between the connection plug418and the interface plate408. In some embodiments, the connection plug418may also be non-conductive. In such applications, the connector pins412a,412bmay be connected to a current source via their respective bottom portions413a,413b.In further applications, the non-conductive elements414a,414band the electrical connection plug418may 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 pins412a,412bmay have various geometries, which will be described in greater detail below. The O-ring420may be provided to seal the electrical connection plug418to the interface plate408. Similarly, the O-rings416a,416bmay be provided to seal the non-conductive sleeves414a,414bto the electrical connection plug418and to seal the connector pins412a,412bto the non-conductive sleeves414a,414b. As depicted, the O-rings416a,416b,and420may fit within recesses formed in the interface plate408and the various components of the electrical contact assemblies. In some exemplary embodiments, the non-conductive sleeves414a,414bmay be affixed (e.g., crimped, soldered, welded, bonded, or the like) to the bottom portions413a,413bof the connector pins412a,412b.In such cases, the O-rings416a,416bbetween these pieces may be eliminated.

FIGS. 5A-5C,FIG. 6, andFIGS. 7A-7Billustrate various exemplary connector pins that can be used with in the heated platens122,200,300,400described 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 toFIGS. 5A-5C, various views of an exemplary connector pin500are shown. As can be seen, the connector pin500includes generally cylindrical bottom and top portions510,520. In the illustrated embodiment, the top portion520has an outside diameter that is larger than the outside diameter of the bottom portion. The bottom portion510may be a solid cylindrical element having a diameter sized to be received within the electrical connection assemblies depicted in either ofFIGS. 2-4. For example, the bottom portion510may have a diameter such that the banana clip216(FIG. 2) may make electrical connection with the connector pin500and retain the connector pin500in the electrical connection assembly. Alternatively, the bottom portion510may have a diameter such that it may be received within the annular opening in the conductive sleeve314ofFIG. 3or the conductive sleeves414a,414bofFIG. 4. In other embodiments, the diameter of the bottom portion510may be sized so that the conductive sleeves314,414a,or414bmay be crimped around the bottom portion510and therefore attached to the connector pin500. It will be appreciated that the bottom portion510needn't be cylindrical, but could have other geometric shapes.

The top portion520of the connector pin500may include a spring structure522and an electrical contact surface524. In the illustrated embodiment, the spring structure522is connected at one end to the bottom portion510of the connector pin500, while the electrical contact surface524is disposed at an opposite end of the spring structure. The connector pin500may have a length “L” while the spring structure522may have a spring length “SL.” In the illustrated embodiment, the spring structure522runs the length of the top portion520. It will be appreciated, the top portion520can 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 structure522may 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 terminals206,306,406a,or406b) and the electrical contact surface524over 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 plate130may warp and bow as its temperature moves through the range of operating temperatures, the connector pin500can be configured to maintain electrical contact between the electrical contact surface524and an associated terminal as the dielectric plate warps or bows. In some examples, the spring structure522may have a preload force of between approximately 5 and 25 Newtons. In some examples, the spring structure522may have a preload force of approximately 10 Newtons.

FIG. 5Bshows a first side view of the connector pin500, including bottom portion510, spring structure522and the electrical contact surface524.FIG. 5Cshows a second side view of the connector pin500rotated 90-degrees with respect to the side view ofFIG. 5B. As can be seen, the spring structure522includes a plurality of leaves526that are spaced apart from immediately adjacent leaves by a gap “g.” The plurality of leaves526are connected to adjacent leaves via bridge elements527disposed, in alternating fashion, on opposite sides of the spring structure. By positioning the bridge elements527in this alternating arrangement the spring structure is provided an accordion shape.

Some or all of the bridge elements527may include central and/or peripheral cutouts529,531. These cutouts529,531can serve to control heat transfer through the spring structure522while also providing the spring structure with a desired biasing force.

In some embodiments the connector pin500may be formed from a single piece of material. In some examples, the plurality of alternating leaves526, bridge elements527and cutouts529,531may 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 pin500. For example, if the connector pin500is 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 pin500may be formed from tungsten, molybdenum, Inconel, titanium or combinations thereof.

FIG. 6illustrates a block diagram showing a further exemplary connector pin600. In general, the connector pin600may have a shape, structure and configuration similar to the connector pins described in relation toFIGS. 5A-5C. For example, the connector pin600may include a bottom portion610and a top portion620including a spring structure622formed from a plurality of alternating leaves626. The electrical contact surface624of the connector pin600, however, is domed, as opposed to being generally flat like that depicted inFIGS. 5A-5C. Thus, the electrical contact surface624may have a radius of curvature “R,” which in some embodiments may be about 1-inch. Furthermore, the electrical contact surface624may be generally convex (as depicted) for the purpose of increasing the area where the electrical contact surface624meets the terminal (e.g., the terminals206,306,406a,or406b) of the heated platen. More particularly, the generally convex shaped electrical contact surface624may operate to concentrate the point of electrical contact in one region in order to create a more robust electrical path.

FIGS. 7A-7Billustrate various views of an additional exemplary connector pin700. As can be seen, the connector pin700includes generally cylindrical bottom and top portions710,720. In the illustrated embodiment, the top portion720has an outside diameter that is larger than the outside diameter of the bottom portion. The bottom portion710may have a diameter sized to be received by the electrical connection assemblies depicted in either ofFIGS. 2-4. For example, the bottom portion710may have a diameter such that the banana clips216(FIG. 2) may make electrical connection with the connector pin700and retain the connector pin700in the electrical connection assembly. Alternatively, the bottom portion710may have a diameter such that it may be inserted into the annular opening in the conductive sleeve314ofFIG. 3or the conductive sleeves414a,414bofFIG. 4. Furthermore, the diameter may be such that the conductive sleeves314,414a,or414bmay be crimped around the bottom portion710and therefore attached to the connector pin700. It will be appreciated that the bottom portion710needn't be cylindrical, but could have other geometric shapes.

The top portion720of the connector pin700may include a spring structure722, and an electrical contact surface724disposed at an end of the top portion720opposite the bottom portion710. The spring structure722may take the form of a helical coil spring, including a plurality of coil elements725separated by spaces727. The top portion720may have a central opening721therein, such that the electrical contact surface724is 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 pin700may have an overall length “L,” and the spring structure722may have a spring length “SL.” In the illustrated embodiment, the top portion720includes a non-spring portion723disposed between the spring structure722and the bottom portion710. As will be appreciated, the spring length “SL,” along with other geometric aspects of the spring structure722can be adjusted to provide a desired biasing force as will be described below.

As with previous embodiments, the spring structure722may be biased to maintain electrical contact between a terminal (e.g., the terminals206,306,406a,or406b) and the electrical contact surface724over a range of operating temperatures. In some examples, the range of operating temperatures is 150 to 600° C. Because the dielectric plate130may warp and bow as its temperature moves through the range of operating temperatures, the connector pin700can maintain electrical contact with the terminal as the dielectric plate warps or bows. In some examples, the spring structure722may have a biasing force of between approximately 5 and 25 Newtons. In some examples, the spring structure722may 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 structure722, including the spring length “SL,” the diameter of the opening721and the thickness “T” of the coil elements725. Although the illustrated embodiment shows the coil elements725being of substantially equal thickness “T,” it will be appreciated that the coil elements725can have different thicknesses. In addition, the opening721is shown as being substantially cylindrical, however, it could have a varied cross-sectional shape (e.g., tapered) to provide the spring structure722(and resulting connector pin700) with a desired biasing characteristic.

In some embodiments, the connector pin700may 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 pin700. For example, if the connector pin700is 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 pin700may be formed from tungsten, molybdenum, Inconel, titanium or combinations thereof. In one embodiment the connector pin700is formed from a TZM (titanium-zinc-molybdenum) alloy.

FIG. 7Bis a side view of the connector pin700. As depicted, the spring structure722includes a number of helical coils726. In some examples, the helical coils726may be formed by cutting helical grooves in the top portion720using, 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 inFIG. 7A.

It is to be appreciated, that the methods of forming the connector pins500,600, and700described 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.