Patent Publication Number: US-10319579-B2

Title: Adapter for replaceable lamp

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/546,103, filed on Nov. 18, 2014, which application claims priority to U.S. Provisional Patent Application Ser. No. 61/918,451, filed on Dec. 19, 2013, both of which are herein incorporated by reference. 
    
    
     BACKGROUND 
     Field 
     Embodiments of the present disclosure generally relate to an apparatus for thermally processing a substrate. In particular, embodiments of the present disclosure relate to an adapter for lamps used as a source of heat radiation in a rapid thermal processing (RTP) chamber. 
     Description of the Related Art 
     During RTP of substrates, thermal radiation is generally used to rapidly heat a substrate in a controlled environment to a maximum temperature of up to about 1350° C. This maximum temperature is maintained for a specific amount of time ranging from less than one second to several minutes depending on the particular process. The substrate is then cooled to room temperature for further processing. 
     High voltage, e.g., about 40 volts to about 130 volts, tungsten halogen lamps are commonly used as the source of heat radiation in RTP chambers. Current lamp assembly designs include a lamp body, a bulb and a base coupling to the lamp body. The lamp base mates to a receptacle on a printed circuit board (PCB) structure, facilitating easy removal and replacement of the lamp assembly. When the bulb fails, the entire lamp assembly including the base coupling to the lamp body is replaced even though the base itself is functioning properly. Replacement of a functional base due to a faulty bulb causes unnecessary waste and expense. 
     Therefore, it is desirable to provide an improved lamp design to reduce cost and provide ability to adjust height of the lamps as needed. 
     SUMMARY OF THE DISCLOSURE 
     Embodiments of the disclosure generally relate to an improved adapter for lamps used as a source of heat radiation in a rapid thermal processing (RTP) chamber. In one embodiment of the present disclosure, a lamp assembly is provided. The lamp assembly includes a capsule having a filament disposed therein, a press seal coupling to the capsule, and an adapter having a receptacle contoured to receive at least a portion of the press seal, wherein the press seal is removably engaged with the adapter. 
     In another embodiment, a lamp assembly for use in a thermal processing chamber is provided. The lamp assembly includes a lamp element comprising a capsule having a filament disposed therein, a press seal extending from the capsule, a first filament lead and a second filament lead, the first and second filament leads extend from the filament to a first metal foil and a second metal foil disposed within the press seal, respectively, and a first electrically conductive lead and a second electrically conductive lead, the first and second electrically conductive leads electrically connect the first and second metal foils to respective electrically conductive receptacles formed in a printed circuit board (PCB) structure positioned external to the lamp assembly, and an adapter having an opening at first and second ends thereof, wherein the opening at the first end has a receptacle contoured to receive at least a portion of the press seal, and the receptacle is configured to removably engage with the press seal. 
     In yet another embodiment, an adapter for a lamp element is provided. The adapter includes an elongate body having a first end and a second end opposing the first end, wherein an opening at the first end has a receptacle contoured to receive at least a seal portion of a lamp element to be removably engaged with the elongate body, wherein the seal portion encapsulates and creates a hermetic seal about a metal foil connected to a filament of the lamp element. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIG. 1  is a schematic, cross-sectional view of a thermal processing chamber having an array of lamp assemblies. 
         FIG. 2  is a schematic, top view of the array of the lamp assemblies in a cooling chamber of the thermal processing chamber. 
         FIG. 3  is a schematic, cross-sectional view of a lamp assembly according to embodiments of the disclosure. 
         FIGS. 4A-4F  are schematic depictions of exemplary lamp element designs that may be used to engage with an adapter according to embodiments of the disclosure. 
         FIG. 5  is a front schematic, cross-sectional view of an exemplary lamp assembly according to embodiments of the disclosure. 
         FIG. 6A  is a schematic sectional view of an exemplary lamp assembly according to embodiments the disclosure. 
         FIG. 6B  is a schematic perspective view of  FIG. 6A . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the disclosure generally relate to an improved adapter for lamps used as a source of heat radiation in a rapid thermal processing (RTP) chamber. The improved adapter allows an easy, fast replacement of a lamp element by making the lamp element removably engaged with the adapter so that the lamp element and/or the adapter can be individually replaced. In some aspects of various embodiments of this disclosure, the adapter may be permanently affixed (brazed, welded, interference fit, or glued etc.) in the lamphead assembly. The lamp element is configured to provide sufficient rigidity to handle compressive forces of inserting the lamp assembly into a PCB structure. The adapter may optionally provide a fuse (and/or electrical receptacles for the lamp element) which can be replaced from the side, top, or bottom of the adapter. The adapter provides a receptacle for receiving a portion of the lamp element. The receptacle is contoured and may be coated to aid in directing thermal radiation to the target in a controlled manner. The adapter may provide thermal conductive features and a cooling path to facilitate heat transfer from the lamp element to the outside world. As a result, the lamp can be operated so that critical parts are at a temperature low enough to permit long lamp life. Details of various embodiments are discussed below. 
     Exemplary Chamber Hardware 
       FIG. 1  is a schematic, cross-sectional view of an RTP chamber  100  in which embodiments of the present disclosure are used. The RTP chamber  100  is capable of providing a controlled thermal cycle that heats the substrate  164  for processes such as, for example, thermal annealing, thermal cleaning, thermal chemical vapor deposition, thermal oxidation and thermal nitridation. It is contemplated that embodiments of the present disclosure may also be used in epitaxial deposition chambers which are heated from the bottom, the top, or both, and also other RTP chambers where bottom heating is used. The RTP chamber  100  includes chamber walls  136  enclosing a process zone  138 . For example, the chamber walls  136  enclosing the process zone  138  can comprise sidewalls  140  and bottom walls  144  formed by a main body  152  and a top wall  148  formed by a window  156  resting on the main body  152 . The main body  152  may be made of stainless steel, although aluminum and other suitable materials may also be used. The window  156  is made of a material that is transparent to infrared light, such as clear fused silica quartz. 
     A substrate support  160  holds the substrate  164  during processing in the process zone  138 . The substrate support  160  may include a rotatable structure that rotates the substrate  164  during processing. For example, the support  160  may include a magnetically levitated rotor  168  positioned within a channel  172  in the main body  152 . The magnetically levitated rotor  168  supports a quartz support cylinder  176 , on top of which is a support ring  180  to hold the substrate  164 . A magnetic stator  184  located externally to the channel  172  containing the rotor  168  is used to magnetically induce rotation of the rotor  168  in the channel  172 , which in turn causes rotation of the substrate  164  on the support ring  180 . The substrate  164  may be rotated, for example, at about 100 to about 250 revolutions per minute. 
     A radiation source  188  directs radiation onto the substrate  164 , and can be positioned above the substrate  164 , such as in a ceiling  192  of the RTP chamber  100  above the radiation permeable window  156  at the top of the process zone  138 . The radiation source  188  generates radiation at wavelengths that heat the substrate  164 , such as radiation having wavelengths of from about 200 nm to about 4500 nm. In one embodiment, the radiation source  188  may include a honeycomb array  196  of lamp assemblies  20 . The array  196  may include one or more approximately radial heating zones that can be independently modulated to control temperatures across the substrate  164 . For example, in one aspect, the radiation source  188  may include 409 lamps divided into 15 radially symmetric zones. Each zone can be independently controlled to provide fine control of the radial profile of heat delivered to the substrate  164 . The radiation source  188  is capable of rapidly heating the substrate  164  for thermal processing, for example at a rate of from about 50° C./s to about 280° C./s. 
     Each lamp assembly  20  in the array  196  of lamp assemblies  20  is enclosed in a tubular lamp assembly housing  204 . One end of the lamp assembly housing  204  is adjacent to the transmission window  156 . The lamp assembly housing  204  may have a reflective inner surface  208  to increase the efficiency of light and heat transfer from the lamp assemblies  20  to the substrate  164 . The lamp assembly housing  204  may be enclosed in a fluid cooling chamber  212  defined by upper and lower fluid chamber walls  216 ,  220  and a cylindrical fluid chamber side wall  224 . Clamps  256  secure the main body  152 , window  156 , and cooling chamber  212  together. O-rings  260  are located between the window  156  and the cooling chamber  212  and between the window  156  and the main body  152  to provide a vacuum seal at those interfaces. A cooling fluid, such as, for example, water, can be introduced into the cooling chamber  212  through a cooling fluid inlet  228  and removed from the cooling chamber  212  through a cooling fluid outlet  232 .  FIG. 2  illustrates a top view of the array  196  of lamp assemblies  20  in lamp assembly housings  204  in the cooling chamber  212 . Cooling fluid travels in the space  236  between the lamp assembly housings  204 , and may be directed by baffles  240  to ensure an effective fluid flow to transfer heat from the lamp assemblies  20  in the lamp assembly housings  204 . A vacuum pump  248  is provided to reduce the pressure in the lamp assembly housings  204 . The vacuum pump  248  is coupled to the lamp assembly housings  204  by a conduit  252  in the cylindrical sidewall  224  and grooves in the bottom wall  144  of the cooling chamber  212 . 
     In some embodiments, a pressurized source (not shown) of a thermally conductive gas, such as helium, may be provided and configured to cool the lamp assembly housing  204  with the thermally conductive gas, thereby facilitating thermal transfer between the lamps assemblies  20  and the cooling chamber  212 . The pressurized source may be connected to the lamp assembly housing  204  through a port and a valve. The thermally conductive gas may be introduced in a manner so that the lamp assembly housing  204  (and therefore the lamp assembly  20  disposed therein) is operated under reduced pressure of the thermal conductive gas. 
     The bottom wall  144  of the main body  152  may include a reflective plate  264  positioned below the substrate  164 . One or more temperature sensors  268 , such as pyrometers having fiber optic probes, may also be provided to detect the temperature of the substrate  164  during processing. The sensors  268  are connected to a chamber controller  272 , which can use their output to determine a power level to supply to individual lamp assemblies  20  and to groups of lamp assemblies  20  in a zone. Each group of lamp assemblies  20  can be separately powered and controlled by a multi-zone lamp driver  276 , which is in turn controlled by the controller  272 . 
     A gas supply  280  can provide a process gas into the process zone  138  and control the atmosphere in the RTP chamber  100 . The gas supply  280  includes a source  284  of process gas and a conduit  288  having a flow control valve  292  that connects the source  284  to a gas inlet (not shown) in the RTP chamber  100  to provide gas in the RTP chamber  100 . An exhaust  202  controls the pressure of gas in the RTP chamber  100  and exhausts process gas from the RTP chamber  100 . The exhaust  202  may include one or more exhaust ports  206  that receive spent process gas and pass the spent gas to an exhaust conduit  210  that feeds one or more exhaust pumps  211 . A throttle valve  213  in the exhaust conduit  210  controls the pressure of the gas in the RTP chamber  100 . 
     The RTP chamber  100  may further include a printed circuit board (PCB) structure  297  on top of the upper cooling fluid chamber wall  216 . The PCB structure  297  may include receptacles  299  configured to receive electrical connectors of the lamp assembly  20 . The PCB structure  297  may also include electrical traces and other electrical elements to deliver power and signals to the lamp assemblies  20  from the multi-zone lamp driver  276  and controller  272 . Each of the plurality of lamp assemblies  20  is inserted into the PCB structure  297  for electrical connection through the driver  276  to a power supply source (not shown). 
     Exemplary Lamp Assembly 
       FIG. 3  is a schematic, cross-sectional view of a lamp assembly  300  according to embodiments of the disclosure for use in an RTP chamber, such as the RTP chamber  100 . The lamp assembly  300  may be used in place of the lamp assembly  20  shown in  FIG. 1 . It should be noted that the concept and features described in  FIG. 3  are equally applicable to various embodiments discussed in this disclosure. In general, the lamp assembly  300  includes a lamp element  302  and an adapter  306 . The adapter  306  is configured to removably engage with the lamp element  302 . The lamp element  302  and the adapter  306  in each lamp assembly  20  in the array  196  of lamp assemblies  20  ( FIG. 1 ) are individually replaceable. When the bulb fails, rather than replacing an entire lamp assembly, only the lamp element of the lamp assembly that contains the faulty bulb is replaced. Therefore, the adapter can be reused. Making the adapter and the lamp element removable from each other and interchangeable in the lamp assembly reduces lamp replacement cost once the adapter is purchased. 
     The adapter  306  may have a general tubular or cylindrical body, or elongate body having some of its cross sectional periphery matching the cross sectional periphery of the lamp head where the lamp is normally inserted. The adapter  306  has a first end  304  and a second end  314  opposing the first end  304 . The first end  304  of the adapter  306  has a receptacle  324  contoured to receive the bottom portion of the lamp element  302 , for example the press seal  312 . The lamp element  302  generally includes a light transmissive capsule  308  that contains a filament  310 , and a press seal  312  coupling to the light transmissive capsule  308 . The filament  310  electrically connects to metal foils  318   a ,  318   b  disposed within the press seal  312  by filament leads  316   a ,  316   b , respectively. The press seal  312  encapsulates and creates a hermetic seal about the metal foils  318   a ,  318   b . The metal foils  318   a ,  318   b  may extend out of the press seal  312 . The metal foils  318   a ,  318   b  are in electrical communication with optional electrical connectors  320   a ,  320   b  via electrically conductive wires or leads  322   a ,  322   b  extending through the adapter  306 . The adapter  306  have channels  332   a ,  332   b  configured to allow the passage of the electrically conductive wires or leads  322   a ,  322   b . The channels  332   a ,  332   b  may extend from the receptacle  324  in a direction along a longitudinal axis  303  of the adapter. In some cases where the electrical conductors are sufficiently insulated and do not require additional cooling, the channels  332   a  and  332   b  may be connected to form one channel. 
     In some embodiments, the second end  314  of the adapter  306  may be sealed with a plug  330 . The electrical connectors  320   a ,  320   b  extend through and out of the plug  330  to insert into respective electrically conductive receptacles  299  formed within the PCB structure  297  for distributing power to the filament  310 . In some cases, the electrically conductive wires or leads  322   a ,  322   b  may connect to the electrical connectors  320   a ,  320   b  as shown in  FIG. 3 . If desired, the at least one of the electrically conductive wires or leads  322   a ,  322   b  of the lamp element  302  may have an engagement feature configured to be engaged with electrically conductive receptacles  299  formed within the PCB structure  297 . Alternatively, the electrically conductive wires or leads  322   a ,  322   b  may include additional components to provide sufficient rigidity to the electrically conductive wires or leads  322   a ,  322   b , as will be discussed in more detail below with respect to  FIGS. 4A-4F . In such a case, the electrical connectors  320   a ,  320   b  may be omitted and the electrically conductive wires or leads with enhanced rigidity may be inserted into or engaged with respective electrically conductive receptacles  299  formed within the PCB structure  297 . 
     The adapter  306  may have a mating extension  326  formed in the interior surface  317  of the receptacle  324 . The lamp element  302 , for example the press seal  312 , may have a corresponding groove  328  formed in the exterior surface of the press seal  312 . When the lamp element  302  engaged with the adapter  306 , the mating extension  326  snaps into the groove  328  and locks them into place. Upon engagement of the adapter  306  and the lamp element  302 , a portion or the entire press seal  312  is received within the receptacle  324 . While not discussed, it is contemplated that the adapter  306  and the lamp element  302  may have any other suitable engagement features to allow easy, fast replacement and attachment of the adapter and/or the lamp element. 
     The height of the adapter  306  may vary depending upon the length of the lamp element  302  (i.e., capsule  308  and/or the press seal  312 ) and the configuration of thermal processing chamber. In certain types of thermal processing chamber, a constant distance is required between the lamp assembly and a chamber dome of the thermal processing chamber to provide uniform radiant heating of the substrate. In such a case, the adapter  306  may be made at a uniform size and configured to engage with the lamp element  302  at different heights. Alternatively, the adapter  306  may be made with different heights to engage with the lamp element  302  made with the same height. In various embodiments, the adapter  306  may have a height of about 5 mm to about 240 mm, such as about 8 mm to about 100 mm, for example about 10 mm to about 20 mm, about 20 mm to about 30 mm, about 30 mm to about 40 mm, about 40 mm to about 50 mm, about 50 mm to about 60 mm, about 60 mm to about 70 mm, about 70 mm to about 80 mm, about 80 mm to about 90 mm, about 90 mm to about 100 mm. 
     The adapter  306  may be made with a high thermal conductivity material such as a metal (e.g., copper, aluminum or stainless steel) or ceramic (e.g., aluminum nitride, silicon carbide, alumina, silicon nitride) to facilitate heat transfer between the lamp element  302  and the outside world. In one embodiment, aluminum is utilized for the cylindrical body surrounding the press seal  312  to increase the thermal conductivity of the adapter  306 . In some embodiments, the top surface and/or interior surface  317  of the receptacle  324  may be contoured and coated to aid in directing radiation to the target in a controlled manner or modify the radiant heating of the adapter. For example, the interior surface  317  of the receptacle  324  may be made conical, cylindrical, hemispherical or arcuate in shape and coated with a light reflecting material such as aluminum, protected aluminum, gold or gold-plated aluminum, or even a diffuse reflective material such as titania, alumina, silica, zirconia, or hafnia. The top surface of the receptacle  324  described herein refers to the surface facing the bulb while the interior surface  317  refers to the surface in close proximity to the press seal  312 . A gas gap  350  may be provided between the press seal  312  and the interior surface  317  of the adapter  306 . The gas gap  350  serves as a cooling path to facilitate heat transfer from the lamp element  302  to the outside world. In one example, the gas gap  350  is about 0.005 mm to about 1 mm. The wall thickness of the adapter  306 , particularly the wall surrounding the press seal  312 , may be about 0.5 mm to about 30 mm. It should be noted that the wall thickness may vary for rectangular cross section press seals in circular cross section adapter. 
     To further increase the thermal conductivity of the cylindrical body surrounding the press seal  312 , a higher thermal conductivity compound may be presented between the press seal  312  and the receptacle  324 . In one embodiment, the thermal conductivity compound may have a thermal conductivity of about 1-2 W/(K-m) to about 150 W/(m-k) or higher, for example exceeding 200 W/(m-K). Some possible materials may include, but are not limited to MgPO 4 , ZrSiO 4 , ZrO 2 , MgO, Al 3 N 4 , and SiO 2 . The same thermal conductivity compound may also form on the exposed surfaces of the channels  332   a ,  332   b  to help cooling of the electrically conductive wires or leads  322   a ,  322   b  extending therethough. A combination of one or more of these approaches greatly facilitates transfer of heat away from the lamp bulb and lamp element to the cooling fluid flowing through the lamphead housing surrounding the plurality of lamp assemblies. In most cases, the temperature of the press seal  312  can be kept below about 350° C. As a result, bulb life of the lamp assembly is improved. 
     The lamp element  302  may or may not have a fuse (not shown) in the light transmissive capsule  308  or the press seal  312 . The fuse is generally provided to limit arcing and potential explosion in the lamp during lamp failure. The fuse may be provided external to the light transmissive capsule  308  and the press seal  312  to prevent undesirable cracking or breaking of the capsule during lamp failure. In cases where the lamp element  302  is a simple capsule/fuse style (i.e., the adapter does not contain a fuse and the fuse is incorporated internal or external to the lamp element  302 ), the fuse can be replaced along with the lamp element  302 . In cases where the lamp element  302  is a simple capsule style (i.e., the fuse is not used in the lamp element  302  and may be provided by the adapter), the adapter  306  may optionally provide a fuse to be connected to the electrically conductive wires or leads  322   a ,  322   b . In this case, the lamp element may make electrical connection to receptacles inside the adapter rather than directly to the PCB. Also in this case the fuse can be made separated from the adapter  306  and be replaced through the side or the second end  314  or even the top of the adapter  306 , as will be discussed in further detail below with respect to  FIGS. 6A and 6B . In cases where the fuse is provided external to the light transmissive capsule  308  and the press seal  312 , the lamp element  302  may include additional components to provide sufficient rigidity to the electrically conductive wires or leads  322   a ,  322   b  to absorb the compressive forces applied during insertion of the lamp assembly  300  into the PCB structure  297  (i.e., prevents the fuse from undergoing compression). Various components used to enhance rigidity of the electrically conductive wires or leads are discussed below with respect to  FIGS. 4A-4F . In some embodiments, the fuse may be optionally incorporated in other parts of the circuit, e.g., the PCB board, and not required in the lamp element  302  or the adapter  306 . 
     Exemplary Lamp Elements 
       FIGS. 4A-4F  are schematic depictions of exemplary lamp element designs that may be used to engage with the adapter  306  according to embodiments of the disclosure. The lamp element  400  depicted in each of these Figures generally includes a quartz capsule  402  housing a tungsten filament  404 . Tungsten leads  406   a ,  406   b  extend from the filament  404  and are each attached (e.g., welded) to molybdenum foil  408   a ,  408   b . Molybdenum leads  410   a ,  410   b  are attached (e.g., welded) and extend from the molybdenum foil  408   a ,  408   b . A quartz press seal  412  encapsulates and creates a hermetic seal about the molybdenum foil  408   a ,  408   b . The molybdenum leads  410   a ,  410   b  extend out of the press seal  412 . 
     In each of the  FIGS. 4A-4C , a conductive pin  414  is attached (e.g., welded) to the lead  410   b . In addition, an insulative sleeve  416  (e.g., ceramic or plastic sleeve), a fuse  418 , and a conductive pin  420  are attached to the lead  410   a . The fuse  418  composition may be from the same family of metals used for lamp fuses, such as nickel, zinc, copper, silver, aluminum, and alloys thereof. Once the lamp element  400  is engaged with the adapter  306  (or various adapter designs shown in  FIGS. 5 and 6A-6B ), the conductive pin  414  and the conductive pin  420  extend through the channels  332   a ,  332   b  formed within the adapter  306  and are inserted into or engaged with respective electrically conductive receptacles  299  formed within the PCB structure  297  for connection to a power supply. 
     In the embodiment shown in  FIG. 4A , the insulative sleeve  416  may have a thin metallic layer  422  deposited over the inner surface  417  of the sleeve  416 . The equivalent cross-section of the metallic layer  422  (normal to the current flow) approximately corresponds to that of a fuse wire or ribbon designed for this application. Likewise the metallic layer  422  composition may be from the same family of metals used for lamp fuses, e.g., nickel, zinc, copper, silver, aluminum, and alloys thereof. The lead  410   a  and the conductive pin  420  are electrically connected to the metallic layer  422 , e.g., soldered, brazed, interference fitted or compression fitted. The thin metallic layer  422  is constructed to act as the fuse  418 . 
     In the embodiment shown in  FIG. 4B , the insulative sleeve  416  may have a thin metallic trace  424  deposited along one side of the inner surface  417  of the sleeve  416 . The lead  410   a  and the conductive pin  420  are fixed to the sleeve  416  in electrical contact with the trace  424 , which acts as the fuse  418 . The lead  410   a  and the conductive pin  420  may be attached to the sleeve  416  using a ceramic compound, a high temperature epoxy, a high temperature phenolic resin, or shrink tubing, for example. The trace  424  can be extended to cover the entire inner diameter for a short axial extent at the top and bottom of the insulative sleeve  416  to permit attachment of the sleeve  416  to the conductive pin  420  and the lead  410   a  by soldering or brazing. 
     In the embodiment shown in  FIG. 4C , a wire fuse  418  is attached (e.g., welded, soldered) to the lead  410   a  and extends through the insulative sleeve  416 . The fuse  418  is further attached (e.g., welded, soldered) to the conductive pin  420 . The lead  410   a  and the conductive pin  420  may be attached to the sleeve  416  using a ceramic compound, a high temperature epoxy, a high temperature phenolic resin, or shrink tubing, for example. For any of the designs shown in  FIGS. 4A, 4B, and 4C , the insulative sleeve  416  may be filled with low melting point glass beads or insulating particles to act as an arc quenching type fuse. 
     Therefore, each of the lamp elements  400  depicted in  FIGS. 4A-4C  provides for connection between the leads  410   a ,  410   b  and the conductive pins  414 ,  420  to be inserted into or engaged with the PCB structure  297  shown in  FIG. 1 , without requiring the use of ceramic potting compound or any thermal conductivity compound in the lamp elements  400  as opposed to prior art high voltage, tungsten halogen lamps. In most cases, the ceramic potting compound or thermal conductivity compound may be eliminated from the lamp assembly even after the lamp element  400  is engaged with the inventive adapter as discussed in  FIGS. 3, 5 and 6 . Once the lamp element  400  is engaged with the adapter (e.g., adapter  306  or various adapter designs shown in  FIGS. 5 and 6A-6B ), the insulative tube configuration can provide the rigidity to absorb the compressive forces applied during insertion of the conductive pins  414 ,  420  into the PCB structure  297 . 
     Although each of the  FIGS. 4A-4C  depicts a conductive pin  414  attached to the lead  410   b , in embodiments shown in  FIGS. 4D-4F , the lead  410   b  is attached to an additional insulative sleeve  416  (e.g., ceramic or plastic sleeve), an additional fuse  418 , and an additional conductive pin  420  in the same manner as shown with regard to lead  410   a . Additionally, each of the pins  414  and  420  may be configured to be compatible with mating receptacles  299  formed in the PCB structure  297 . 
     Other suitable lamp elements that may be used to engage with the adapter  306  (or various adapter designs shown in  FIGS. 5 and 6A-6B ) are further described in U.S. Patent Application Ser. No. 61/787,805, filed on Mar. 15, 2013, entitled “SIMPLIFIED LAMP DESIGN,” which is incorporated herein by reference in its entirety and for all purposes. 
       FIG. 5  is a front schematic, cross-sectional view of an exemplary lamp assembly  500  according to embodiments of the disclosure for use in an RTP chamber, such as the RTP chamber  100 . The lamp assembly  500  may be used in place of the lamp assembly  20  shown in  FIG. 1 . The lamp assembly  500  generally includes a lamp element  501  and an adapter  513 . The lamp element  501  may be a simple capsule/fuse style, i.e., the adapter  513  does not contain a fuse and the fuse is made external to the lamp element  501 . The lamp element  501  includes a capsule  502  housing a filament  504 , and a press seal  512  coupling to the capsule  502 . The capsule  502  may have a variety of shapes, including but not limited to tubular, conical, spherical, and multi-arcuate shapes. The press seal  512  may have a shape corresponding to that of the capsule  502  or may be in any shape to allow extension of filament leads  506   a ,  506   b  from the filament  504  to metal foils  508   a ,  508   b . In one embodiment, the press seal  512  is of elongate substantially rectangular shape. Metal leads  510   a ,  510   b  are attached to (e.g., welded) and extended from the metal foil  508   a ,  508   b  through and outside of the press seal  512 . The press seal  512  encapsulates and creates a hermetic seal about the metal foils  508   a ,  508   b.    
     The adapter  513  may have a general tubular or cylindrical body having a first end  523  facing the press seal  512  and a second end  525  opposing the first end  523 . The cylindrical body provides ease of manufacture, although other cross-sectional shapes, such as square, rectangular, triangular and multi-arcuate shapes, are possible. The adapter  513  may have channels  527 ,  529  configured to allow the passage of the metal leads  510   a ,  510   b . Similar to the adapter  306  ( FIG. 3 ), the adapter  513  is configured to removably engage with the press seal  512 . The adapter  513  has a receptacle  509  contoured to receive at least a portion of the press seal  512 . The receptacle  509  of the adapter  513  may have a mating extension  517  formed in its inner circumferential surface  507 . The press seal  512  may have a corresponding groove  515  formed in its outer surface  519 , such that when engaged, the mating extension  517  snaps into the groove  515 , and locks them into place. 
     The adapter  513  may be made of thermal conductive material, for example a metallic material such as copper, aluminum, or stainless steel, to aid in conducting heat away from the lamp element  501 . A gas gap  550  may be provided between the press seal  512  and the inner circumferential surface  507  of the adapter  513  to facilitate heat transfer from the lamp element  501  to the outside world. In one example, the gas gap  550  is about 0.005 mm to about 1 mm. Increasing the thickness of the cylindrical body without increasing the overall outer diameter of the adapter  513  may also improve transfer of heat away from the lamp element  501 . In a non-limiting example the adapter  513  may have an outer diameter of about 2 mm to about 50 mm, for example about 10 mm to about 35 mm, and an inner diameter of about 1 mm to about 49 mm, for example about 9 mm to about 34 mm. The wall thickness of the adapter  513 , particularly the wall surrounding the press seal  512 , may be about 0.5 mm to about 30 mm. A higher thermal conductivity compound may be presented between the press seal  512  and the receptacle  509 . In one embodiment, the thermal conductivity compound may have a thermal conductivity of about 1-2 W/(K-m) to about 150 W/(m-k) or higher, for example exceeding 200 W/(m-K). Some possible materials may include, but are not limited to MgPO 4 , ZrSiO 4 , ZrO 2 , MgO, Al 3 N 4 , and SiO 2 . The same thermal conductivity compound may also form on exposed surfaces of the channels  527 ,  529  to allow cooling of the metal leads  510   a ,  510   b  extending therethrough. 
     During process, most of the thermal energy is conducted away from the press seal  512  laterally (radially) through the gas gap  550 , to the cylindrical body of the adapter  513  and then laterally to the cooling fluid that travels in the space  236  ( FIG. 2 ) between the lamp assembly housings  204 . In most cases, the temperature of the press seal  512  can be kept below about 350° C. As a result, bulb life of the lamp assembly is improved. 
     The lamp element  501  may or may not provide a fuse.  FIG. 5  illustrates an embodiment where the fuse is provided external to the lamp capsule  502 . In this embodiment, the metal leads  510   a ,  510   b  may include additional components as discussed above with respect to  FIGS. 4A-4F  to provide sufficient rigidity to the metal leads  510   a ,  510   b  to absorb the compressive forces applied during insertion of the lamp assembly  500  into the PCB structure  297  (i.e., prevents the fuse from undergoing compression). For example, the metal lead  510   b  may be connected to a conductive pin  514 , which extends through the adapter  513  to be inserted into or engaged with the mating receptacle  299  formed in the PCB structure  297 . In addition, an insulative sleeve  516  (e.g., ceramic or plastic sleeve), a fuse  518 , and a conductive pin  520  may be attached to the metal lead  510   a . The fuse  518  is provided to limit arcing and potential explosion in the lamp during lamp failure, and may be replaced along with the capsule  502  and the press seal  512 . The fuse  518  composition may be from the same family of metals used for lamp fuses, e.g., nickel, zinc, copper, silver, aluminum, and alloys thereof. Once the lamp element  501  is engaged with the adapter  513 , the conductive pin  514 , the insulative sleeve  516 , the fuse  518 , and the conductive pin  520  provide a rigid, conductive extension for inserting the lamp assembly  500  into the printed circuit board (PCB) structure  297 . 
     Optionally, the second end  525  of the adapter  513  may be sealed with a plug  526 . The plug  526  is configured so that the conductive pins  514 ,  520  can pass therethough and engage with the mating receptacle  299  formed in the PCB structure  297 . The plug  526  may be made of rigid or elastomeric material. The plug  526  may be fixed or flexibly positioned to allow movement relative to the second end  525  of the adapter  513  in a direction along a longitudinal axis  503  of the adapter  513 , thereby accommodating any misalignment between the lamp assembly and electrical connectors formed in the PCB structure  297 . The material of the plug  526  should withstand high temperatures, for example about 150° C. 
       FIG. 6A  depicts a schematic sectional view of an exemplary lamp assembly  600  according to another embodiment of the disclosure.  FIG. 6B  is a schematic perspective view of  FIG. 6A .  FIG. 6A  is generally similar in concept to  FIGS. 3 and 5  except that the adapter  613  is configured to provide with a fuse that can be replaced from the side or bottom of the adapter  613 . The lamp assembly  600  generally includes a lamp element  601  and an adapter  613 . The lamp element  601  may be a simple capsule style, i.e., the lamp element  601  does not contain a fuse and the fuse is provided by the adapter  613 . The lamp element  601  includes a capsule  602  housing a filament  604 , and a press seal  612  coupling to the capsule  602 . The press seal  612  may be in any shape to allow extension of filament leads  606   a ,  606   b  from the filament  604  to metal foils  608   a ,  608   b . In one embodiment, the press seal  612  is of elongate substantially rectangular shape (better seen in  FIG. 6B ). Metal leads  610   a ,  610   b  are attached to (e.g., welded) and extended from the metal foil  608   a ,  608   b  through and outside of the press seal  612 . The press seal  612  encapsulates and creates a hermetic seal about the metal foils  608   a ,  608   b.    
     The adapter  613  may have a general tubular or cylindrical body, or elongate body having some of its cross sectional periphery matching the cross sectional periphery of the lamp head where the lamp is normally inserted. The adapter  613  has a first end  623  facing the press seal  612  and a second end  625  opposing the first end  623 . Similar to the adapter  306  ( FIG. 3 ), the adapter  613  is configured to removably engage with the press seal  612 . The adapter  613  may have a receptacle  609  contoured to receive at least a portion of the press seal  612 . The adapter  613  may have sockets  627 ,  629  extending within the adapter  613  in a direction along a longitudinal axis  603  of the adapter  613 . The sockets  627 ,  629  are configured to allow for the insertion of the metal leads  610   a ,  610   b . In some embodiments, the sockets  627 ,  629  may incorporate retention feature to be engaged or disengaged with corresponding retention features provided on the metal leads  610   a ,  610   b . The retention features disclosed in this disclosure may include laterally operative elements such as a contact spring, a spring-loaded member, a slider, a notch or groove, etc. The sockets  627 ,  629  may be in electrical connection with respective conductive pins  620 ,  614  formed through the adapter  613 . The receptacle  609  of the adapter  613  may have a mating extension  617  formed in its inner circumferential surface  607 . The press seal  612  may have a corresponding groove  615  formed in its outer surface  619 , such that when engaged, the mating extension  617  snaps into the groove  615 , and locks them into place. 
     To improve heat dissipation away from the lamp element  601 , the adapter  613  may be made of thermal conductive material similar to the adapter  513 . A gas gap  650  may be formed between the press seal  612  and the inner circumferential surface  607  of the adapter  613  to facilitate heat transfer from the lamp element  601  to the outside world. In one example, the gas gap  650  is about 0.005 mm to about 1 mm. Similarly, increasing the thickness of the cylindrical body without increasing the overall outer diameter of the adapter  613  may further improve transfer of heat away from the lamp element  601 . In a non-limiting example the adapter  613  may have an outer diameter of about 2 mm to about 50 mm, for example about 10 mm to about 35 mm, and an inner diameter of about 1 mm to about 49 mm, for example about 9 mm to about 34 mm. The wall thickness of the adapter  613 , particularly the wall surrounding the press seal  612 , may be about 0.5 mm to about 30 mm. A higher thermal conductivity compound may be presented between the press seal  612  and the receptacle  609 . In one embodiment, the thermal conductivity compound may have a thermal conductivity of about 1-2 W/(K-m) to about 150 W/(m-k) or higher, for example exceeding 200 W/(m-K). Some possible materials may include, but are not limited to MgPO 4 , ZrSiO 4 , ZrO 2 , MgO, Al 3 N 4 , and SiO 2 . In some cases for example in an electrical socket connection, the same or a different thermal conductivity compound may be formed on exposed surfaces of the sockets  627 ,  629  to allow cooling of the metal leads  610   a ,  610   b  extending therethrough. 
     During process, most of the thermal energy is conducted away from the press seal  612  laterally (radially) through the gas gap  650 , to the cylindrical body of the adapter  613  and then laterally to the cooling fluid that travels in the space  236  ( FIG. 2 ) between the lamp assembly housings  204 . In most cases, the temperature of the press seal  612  can be kept below about 350° C. As a result, bulb life of the lamp assembly is improved. 
     In one embodiment, fuses  618   a ,  618   b  are electrically attached (e.g., welded) between the conductive pins  620 ,  614  and electrical connectors  620 ,  622 . In another embodiment, either one of the fuses  618   a ,  618   b  may be replaced with a conductive wire or lead. The adapter  613  may provide one or more cut-outs  652  sized enough to allow access to fuses  618   a ,  618   b  for service through the cut-out  652  of the adapter  613 . The cut-out  652  may be formed in the sidewall  633  of the cylindrical body of the adapter  613 . Alternatively, the fuses  618   a ,  618   b  can be replaced through the second end  625  of the adapter  613 . In certain embodiments where the lamp element  601  is operated at low voltage (e.g., 12 V), both fuses  618   a ,  618   b  may be replaced with conductive wire or lead, or the metal leads  610   a ,  610   b  can be simply extended through an optional plug  626  that seals the second end  625  of the adapter  613 . 
     Once the lamp element  601  is engaged with the adapter  613 , the conductive pin  620 ,  614  (or electrical connectors  620 ,  622  if used) of the lamp assembly  600  are then inserted into or engaged with respective electrically conductive receptacles  299  formed within the PCB structure  297  for connection to a power supply. It should be noted that in various embodiments of this disclosure, the lamp assembly  300  and  500  may directly connect the lamp element with the PCB structure while the lamp assembly  600  may include two sets of electrical connections: (1) PCB structure  297  to the lamp adapter, and (2) the lamp adapter to the lamp element. Alternatively, the lamp assembly may be configured to connect the lamp element directly with the PCB structure  297 . 
     Embodiments of the lamp assembly discussed in  FIGS. 3, 5 and 6A-6B  may be beneficial to certain thermal processing chambers having an improved PCB structure configured to allow an easy, fast replacement of the lamp assembly, without moving the entire lamphead assembly or the PCB structure. For example, the PCB structure  297  may be provided with a plurality of openings (corresponding to the locations of the lamp assemblies) sized to allow the passage of the lamp assembly, such as lamp assemblies  300 ,  500 , and  600 , therethrough for fast lamp replacement and ease of service of the lamphead assembly. In such a case, the electrical connectors of the lamp assemblies  300 ,  500 , and  600  may have electrical connection features configured in electrical communication with electrical contact terminals provided within or around the openings to securely position and power the lamps in the lamp assembly from a power source. 
     The PCB structure may be a single flat circuitry board, or consisted of multiple concentric ring-type circuitry boards configured in a stepped staircase fashion in accordance with the angle of the chamber dome so that a distance between the lamps and the chamber dome is kept constant. In either case, the lamp element may have the same general size and the height of the adapters may be gradually increased in a radially outward direction from the center of the PCB structure to the peripheral of the PCB structure, or vice versa (i.e., adapters made at same general size and lamp elements made at different heights). Exemplary PCB structure with openings and adapters with various electrical connection features are further described in U.S. Patent Application Ser. No. 61/907,847, filed on Nov. 22, 2013, entitled “EASY ACCESS LAMPHEAD,” which is incorporated herein by reference in its entirety and for all purposes. 
     Benefits of the present disclosure include an easy, fast replacement of a lamp element by making the lamp element removably engaged with the adapter so that the lamp element and/or the adapter can be individually replaced. Making the adapter and the lamp element removable from each other and interchangeable in the lamp assembly reduces lamp replacement cost once the adapter is purchased. Depending upon the style of the lamp element, the adapter may provide an optional fuse which can be replaced from the side or bottom of the adapter. The adapter may provide a receptacle contoured and may be coated to aid in directing thermal radiation to the target in a controlled manner. The adapter may provide features and a cooling path to facilitate heat transfer from the lamp element to the outside world. As a result, the lamp can be operated with press seal temperature low enough to permit long lamp life. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.