Patent Publication Number: US-2007116888-A1

Title: Method and system for performing different deposition processes within a single chamber

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is related to U.S. Ser. No. 11/090,255, Attorney Docket No. 267366US, Client Ref. No. TTCA 19, entitled “A PLASMA ENHANCED ATOMIC LAYER DEPOSITION SYSTEM”, now U.S. Pat. Appl. Publ. No. 2004VVVVVVVVVV, the entire contents of which are incorporated herein by reference. This application is related to U.S. Ser. No. 11/084,176, entitled “A DEPOSITION SYSTEM AND METHOD”, Attorney Docket No. 265595US, Client Ref. No. TTCA 24, now U.S. Pat. Appl. Publ. No. 2004VVVVVVVVVV, the entire contents of which are incorporated herein by reference. This application is related to U.S. Ser. No. ______, entitled “A PLASMA ENHANCED ATOMIC LAYER DEPOSITION SYSTEM HAVING REDUCED CONTAMINATION”, Client Ref. No. TTCA 27, now U.S. Pat. Appl. Publ. No. 2004VVVVVVVVVV, the entire contents of which are incorporated herein by reference. This application is related to U.S. Ser. No. ______, entitled “A DEPOSITION SYSTEM AND METHOD FOR PLASMA ENHANCED ATOMIC LAYER DEPOSITION”, Attorney Docket No. 2274020US, Client Ref. No. TTCA 55, now U.S. Pat. Appl. Publ. No. 2006VVVVVVVVVV, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION  
      1. Field of Invention  
      The present invention relates to a deposition system and a method of operating thereof, and more particularly to a deposition system having multiple process spaces for material deposition.  
      2. Description of Related Art  
      Typically, during materials processing, when fabricating composite material structures, plasma is employed to facilitate the addition and removal of material films. For example, in semiconductor processing, a dry plasma etch process is often utilized to remove or etch material along fine lines or within vias or contacts patterned on a silicon substrate. Alternatively, for example, a vapor deposition process is utilized to deposit material along fine lines or within vias or contacts on a silicon substrate. In the latter, vapor deposition processes include chemical vapor deposition (CVD), and plasma enhanced chemical vapor deposition (PECVD).  
      In PECVD, plasma is utilized to alter or enhance the film deposition mechanism. For instance, plasma excitation generally allows film-forming reactions to proceed at temperatures that are significantly lower than those typically required to produce a similar film by a thermal CVD process that thermally heats the process gas (without plasma excitation) to temperatures near or above the dissociation temperature of the process gas. In addition, plasma excitation may activate film-forming chemical reactions that are not energetically or kinetically favored in thermal CVD. The chemical and physical properties of PECVD films may thus be varied over a relatively wide range by adjusting process parameters.  
      More recently, atomic layer deposition (ALD) and plasma enhanced ALD (PEALD) have emerged as candidates for ultra-thin gate film formation in front end-of-line (FEOL) operations, as well as ultra-thin barrier layer and seed layer formation for metallization in back end-of-line (BEOL) operations. In ALD, two or more process gases, such as a film precursor and a reduction gas, are introduced alternatingly and sequentially while the substrate is heated in order to form a material film one monolayer at a time. In PEALD, plasma is formed during the introduction of the reduction gas to form a reduction plasma. To date, ALD and PEALD processes have proven to provide improved uniformity in layer thickness and conformality to features on which the layer is deposited, albeit these processes are slower than their CVD and PECVD counterparts.  
     SUMMARY OF THE INVENTION  
      One object of the present invention is directed to addressing various problems with semiconductor processing at ever decreasing line sizes where conformality, adhesion, and purity are becoming increasingly important issues affecting the resultant semiconductor device.  
      Another object of the present invention is to reduce contamination problems between interfaces of subsequently deposited material layers.  
      Another object of the present invention is to provide a deposition system capable of changing a process volume size in order to accommodate different deposition processes.  
      Another object of the present invention is to provide a configuration compatible for vapor deposition and plasma enhanced vapor deposition processes within the same system.  
      Variations of these and/or other objects of the present invention are provided by certain embodiments of the present invention.  
      In one embodiment of the present invention, a method is provided for processing a substrate, including disposing a substrate in a vapor deposition system having a process space defined above the substrate, introducing a first process gas composition to the process space according to a first vapor deposition process, depositing a first film on the substrate, introducing a second process gas composition into a second process space different in size from the first process space, and depositing a second film on the substrate from the second process gas composition.  
      In another embodiment of the present invention, a system for thin film vapor deposition on a substrate is provided that includes a process chamber with a first process space having a first volume. The process chamber further includes a second process space that includes at least a part of the first process space and that has a second volume different from the first volume. The first process space is configured for a first chemical vapor deposition, and the second process space is configured for a second chemical vapor deposition.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In the accompanying drawings, a more complete appreciation of the present invention and many attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:  
       FIG. 1  depicts a schematic view of a deposition system in accordance with one embodiment of the present invention;  
       FIG. 2  depicts a schematic view of the deposition system of  FIG. 1  showing an enlarged process space in accordance with one embodiment of the present invention;  
       FIG. 3  depicts a schematic view of a deposition system in accordance with another embodiment of the invention;  
       FIG. 4  depicts a schematic view of the deposition system of  FIG. 3  showing an enlarged process space in accordance with one embodiment of the present invention;  
       FIG. 5  depicts a schematic timing diagram according to one embodiment of the present invention to be used in the deposition systems of  FIGS. 1-4 ; and  
       FIG. 6  shows a process flow diagram of a process in accordance with one embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      In the following description, in order to facilitate a thorough understanding of the invention and for purposes of explanation and not limitation, specific details are set forth, such as a particular geometry of the deposition system and descriptions of various components. However, it should be understood that the invention may be practiced in other embodiments that depart from these specific details.  
      Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views,  FIG. 1  illustrates a deposition system  1  for depositing a thin film, for example a barrier film, on a substrate using a vapor deposition process, such as a chemical vapor deposition (CVD) process, a plasma enhanced CVD (PECVD) process, an atomic layer deposition (ALD) process, or a plasma enhanced ALD (PEALD) process. During the metallization of inter-connect and intra-connect structures for semiconductor devices in back-end-of-line (BEOL) operations, a thin conformal barrier layer may be deposited on wiring trenches or vias to minimize the migration of metal into the inter-level or intra-level dielectric, a thin conformal seed layer may be deposited on wiring trenches or vias to provide a film with acceptable adhesion properties for bulk metal fill, and/or a thin conformal adhesion layer may be deposited on wiring trenches or vias to provide a film with acceptable adhesion properties for metal seed deposition. In addition to these processes, a bulk metal such as copper must be deposited within the wiring trench or via.  
      Oftentimes, for thin conformal films, i.e., barrier layers or seed layers, in back end metallization schemes, it is desirable to use a non-plasma deposition process, such as a thermal vapor deposition process, when depositing the initial thin conformal film over interlevel or intralevel dielectric. Particularly, when this dielectric layer comprises a low dielectric constant (low-k) material, exposure to plasma can cause damage to the low-k layer, that may, for example, affect an increase in the dielectric constant of the film. After using a thermal vapor deposition process to deposit the initial layer, a plasma assisted deposition process may be utilized to improve deposition rate or film morphology or both.  
      These processes in the past typically could require separate chambers customized to the particular needs of each of these processes as no single chamber could accommodate all of the process requirements. For example, a thin film barrier layer is preferably performed at a self-limited ALD process to provide good conformality. Because ALD requires alternating different process gases, deposition occurs at a relatively slow deposition rate. The present inventors have recognized that performing a thermal ALD process in a small process space volume allows rapid gas injection and an evacuation of the alternating gases, which shortens the ALD cycle. On the other hand, metals, such as tantalum, titanium, tungsten, or copper can be deposited at a faster deposition rate by a thermal CVD process that does not necessarily require alternate gas flows. In this process it may be beneficial to use a larger process space volume to provide more uniform deposition of the material. As another example, described above, depositing one or more layers on a substrate may include a non-plasma process as well as a plasma process. The present inventors have recognized that the non-plasma process can benefit from a small process space volume to increase throughput and/or preserve process gas while a larger process space volume is required to sustain a uniform plasma.  
      The need for separate chambers adds costs due to the multiplicity of deposition units, adds time to the fabrication process due to the transfer between the systems of the process wafer, and (due to the transfer between multiple deposition units) makes contamination of the exposed interfaces a concern which had to be addressed through preventive or remedial measures, thereby adding more costs and complexity to the fabrication process.  
      In  FIG. 1 , deposition system  1  according to one embodiment of the present invention includes a processing chamber  10  having a substrate stage  20  configured to support a substrate  25 , upon which a thin film is to be formed. Additionally, the deposition system  1  as illustrated in  FIG. 1  includes a process volume adjustment system  80  coupled to the processing chamber  10  and the substrate stage  20 , and configured to adjust the volume of the process space adjacent substrate  25 . For example, the process volume adjustment system  80  can be configured to vertically translate the substrate stage  20  between a first position creating a first process space  85  with a first volume (see  FIG. 1 ) and a second position creating a second process space  85 ′ with a second volume (see  FIG. 2 ).  
      As illustrated in  FIGS. 1 and 2 , deposition system  1  can include a substrate temperature control system  60  coupled to the substrate stage  20  and configured to elevate and control the temperature of substrate  25 . Substrate temperature control system  60  can include temperature control elements, such as a cooling system including a re-circulating coolant flow that receives heat from substrate stage  20  and transfers heat to a heat exchanger system (not shown), or when heating, transfers heat from the heat exchanger system. Additionally, the temperature control elements can include heating/cooling elements, such as resistive heating elements, or thermoelectric heaters/coolers can be included in the substrate stage  20 , as well as the chamber wall of the processing chamber  10  and any other component within the deposition system  1 .  
      In order to improve the thermal transfer between substrate  25  and substrate stage  20 , substrate stage  20  can include a mechanical clamping system, or an electrical clamping system, such as an electrostatic clamping system, to affix substrate  25  to an upper surface of substrate stage  20 . Furthermore, substrate stage  20  can further include a substrate backside gas delivery system configured to introduce gas to the backside of substrate  25  in order to improve the gas-gap thermal conductance between substrate  25  and substrate stage  20 . Such a system can be utilized when temperature control of the substrate is required at elevated or reduced temperatures. For example, the substrate backside gas system can include a two-zone gas distribution system, wherein the helium gas gap pressure can be independently varied between the center and the edge of substrate  25 .  
      The substrate stage  20  along with in vacuo mechanisms to translate the substrate stage and interior mechanisms for substrate temperature control system  60  can constitute a lower chamber assembly of the processing chamber  10 .  
      The processing chamber  10  can further include an upper chamber assembly  30  coupled to a first process material gas supply system  40 , a second process material gas supply system  42 , and a purge gas supply system  44 . As such, the upper chamber assembly  30  can provide the first process material and the second process material to process space  85 . A showerhead design, as known in the art, can be used to uniformly distribute the first and second process gas materials into the process space  85 . Exemplary showerheads are described in greater detail in pending U.S. Patent Application Pub. No. 20040123803, the entire contents of which is incorporated herein by reference in its entirety, and in previously incorporated by reference U.S. Ser. No. 11/090,255.  
      The deposition system  1  may be configured to process 200 mm substrates, 300 mm substrates, or larger-sized substrates. In fact, it is contemplated that the deposition systems described in the present invention may be configured to process substrates, wafers, or LCDs regardless of their size, as would be appreciated by those skilled in the art. Substrates can be introduced to processing chamber  10 , and the substrate may be lifted to and from an upper surface of substrate stage  20  via a substrate lift system (not shown).  
      According to one embodiment of the present invention, the first process material gas supply system  40  and the second process material gas supply system  42  can be configured to sequentially and optionally alternatingly introduce a first process gas material to processing chamber  10  and a second process gas material to processing chamber  10  in order to sequentially and optionally alternatingly deposit first and second films on substrate  25 . The alternation of the introduction of the first process gas material and the introduction of the second process gas material can be cyclical, or it may be acyclical with variable time periods between introduction of the first and second process gas materials. The first and second process gas materials can, for example, include a gaseous film precursor, such as a composition having the principal atomic or molecular species found in the films formed on substrate  25 . The gaseous film precursor can originate as a solid phase, a liquid phase, or a gaseous phase, and may be delivered to processing chamber  10  in a gaseous phase. The first and second process gas materials can, for example, include a reduction gas. For instance, the reduction gas can originate as a solid phase, a liquid phase, or a gaseous phase, and may be delivered to processing chamber  10  in a gaseous phase. Examples of gaseous film precursors and reduction gases are given below.  
      When introducing the first process gas material or the second process gas material to form the first film or the second film, respectively, the gaseous components, i.e., film precursor and reduction gas, of the first process gas material or the second process gas material may be introduced together at the same time to processing chamber  10 . For example, the film precursor and the reduction gas may be mixed or they may be un-mixed prior to introduction to processing chamber  10 . Alternatively, the gaseous components of the first process gas material or the second process gas material may be sequentially and alternatingly introduced to processing chamber  10 . Plasma may or may not be utilized to assist the deposition of the first film and the second film on substrate  25  using the first process gas material and the second process gas material, respectively.  
      The first material supply system  40 , the second material supply system  42 , and the purge gas supply system  44  can include one or more material sources, one or more pressure control devices, one or more flow control devices, one or more filters, one or more valves, or one or more flow sensors. The flow control devices can include pneumatic driven valves, electromechanical (solenoidal) valves, and/or high-rate pulsed gas injection valves. An exemplary pulsed gas injection system is described in greater detail in pending U.S. Patent Application Pub. No. 20040123803, the entire contents of which are incorporated herein by reference.  
      Referring still to  FIG. 1 , the deposition system  1  in one embodiment of the present invention can include a plasma generation system configured to generate plasma during at least a portion of the sequential and optional alternating introduction of the first process gas material and the second process gas material to processing chamber  10 . The plasma generation system can include a first power source  50  coupled to the processing chamber  10 , and configured to couple power to the first process gas material, or the second process gas material, or both, or gaseous components of the first process gas material, or gaseous components of the second process gas material. The first power source  50  may include a radio frequency (RF) generator and an impedance match network (not shown), and may further include an electrode (not shown) through which RF power is coupled to plasma in processing chamber  10 . The electrode can be formed in the upper assembly  30 , and it can be configured to oppose the substrate stage  20 .  
      The impedance match network can be configured to optimize the transfer of RF power from the RF generator to the plasma by matching the output impedance of the match network with the input impedance of the processing chamber, including the electrode, and plasma. For instance, the impedance match network serves to improve the transfer of RF power to plasma in plasma processing chamber  10  by reducing the reflected power. Match network topologies (e.g. L-type, π-type, T-type, etc.) and automatic control methods are well known to those skilled in the art. A typical frequency for the RF power can range from about 0.1 MHz to about 100 MHz. Alternatively, the RF frequency can, for example, range from approximately 400 kHz to approximately 60 MHz, By way of further example, the RF frequency can, for example, be approximately 13.56 or 27.12 MHz.  
      The deposition system  1  in one embodiment of the present invention can include a substrate bias generation system configured to generate a plasma during at least a portion of the alternating and cyclical introduction of the first process gas material and the second process gas material to processing chamber  10 . The substrate bias system can include a second power source  52  coupled to the processing chamber  10 , and configured to couple power to substrate  25 . The second power source  52  may include a radio frequency (RF) generator and an impedance match network, and may further include an electrode through which RF power is coupled to substrate  25 . The electrode can be formed in substrate stage  20 . For instance, substrate stage  20  can be electrically biased with a DC voltage or at an RF voltage via the transmission of RF power from an RF generator (not shown) through an impedance match network (not shown) to substrate stage  20 . A typical frequency for the RF bias can range from about 0.1 MHz to about 100 MHz. RF bias systems for plasma processing are well known to those skilled in the art. Alternately, RF power can be applied to the substrate stage electrode at multiple frequencies. Alternatively, the RF frequency can, for example, range from approximately 400 kHz to approximately 60 MHz, By way of further example, the RF frequency can, for example, be approximately 13.56 or 27.12 MHz. The substrate bias generation system may operate at a different or the same frequency as the plasma generation system.  
      Although the plasma generation system and the substrate bias system are illustrated in  FIG. 1  as separate entities, these systems may include one or more power sources coupled to substrate stage  20 .  
      Furthermore, the processing chamber  10  is coupled to a pressure control system  32 , including for example a vacuum pumping system  34  and a valve  36 , through a duct  38 . The pressure control system  34  is configured to controllably evacuate the processing chamber  10  to a pressure suitable for forming the thin film on substrate  25 , and suitable for use of the first and second process materials.  
      The vacuum pumping system  34  can include a turbo-molecular vacuum pump (TMP) capable of a pumping speed up to about 5000 liters per second (and greater) and valve  36  can include a gate valve for throttling the chamber pressure. In conventional plasma processing devices utilized for dry plasma etch, a 1000 to 3000 liter per second TMP is generally employed. Moreover, a device for monitoring chamber pressure (not shown) can be coupled to the processing chamber  110 . The pressure measuring device can be, for example, a Type 628B Baratron absolute capacitance manometer commercially available from MKS Instruments, Inc. (Andover, Mass.).  
      Referring now to  FIGS. 3 and 4 , a deposition system  1 ′ is illustrated for depositing a thin film, such as a barrier film, on a substrate using a vapor deposition process, such as a chemical vapor deposition (CVD) process, a plasma enhanced CVD (PECVD) process, an atomic layer deposition (ALD) process, or plasma enhanced ALD (PEALD) process according to another embodiment of the present invention. The deposition system  1 ′ includes many of the same features as deposition system  1  illustrated in  FIGS. 1 and 2 , which like reference numerals represent like components. Deposition system  1 ′ further includes a shield  24  configured to surround a peripheral edge of process space  85  in  FIG. 3 , or process space  85 ′ in  FIG. 4 . Substrate stage  20  may further include an outer lip  22  configured to couple with shield  24  when substrate stage  20  is translated upwards to form process space  85 ′. For example, outer lip  22  can be configured to seal with shield  24 . Shield  24  can be configured to permit passage of process gases there through (as in a perforated shield) in order to permit evacuation of process space  85 ′. If shield  24  is not configured to permit evacuation of process space  85 ′, then a separate vacuum pumping system  35  similar to vacuum pumping system  34  can be used to evacuate the process space  85 ′.  
      The shield  24  depicted in  FIGS. 3 and 4  can serve multiple purposes. The shield  24  can provide a simplified cylindrical geometry in which fluid flow in the process spaces  85  and  85 ′ can be more reliably predicted or controlled. By having openings at predetermined positions of the shield (i.e., as in a perforated shield) the fluid flow can be engineered. Likewise, the shield  24  can provide a symmetrical path to electrical ground proximate the plasma edge, which can provide a uniform plasma that can be more reliably predicted or controlled. Furthermore, the shield  24  can be a replaceable unit, collecting deposits that would normally accumulate on the interior of walls  10 . As such, shield  24  can be replaced in normal routine maintenance and extend the time period before the interior of walls  10  needs to be cleaned.  
      Referring now to  FIG. 5 , deposition system  1  or  1 ′ can be configured to perform multiple vapor deposition processes, such as a thermally activated vapor deposition process (i.e., a deposition process not utilizing plasma) followed by a plasma enhanced vapor deposition process (i.e., a deposition process utilizing plasma). The thermally activated vapor deposition process can include a thermal atomic layer deposition (ALD) process or a thermal chemical vapor deposition (CVD) process, and the plasma enhanced vapor deposition process can include a plasma enhanced ALD process or a plasma enhanced CVD process. In one example, when depositing multiple tantalum containing films, a first deposition process such as a thermal ALD or thermal CVD process can be utilized to deposit a first film comprising Ta(C)N, and a second deposition process such as a plasma enhanced ALD process can be utilized to deposit a second film comprising Ta atop the first film.  
      As illustrated in  FIG. 5 , when performing the first deposition process, a first process gas material is introduced to the processing chamber, wherein the first process gas material includes a film precursor comprising tantalum, such as a metal halide (e.g., tantalum pentachloride) or a metal organic (e.g., Ta(NC(CH 3 ) 2 C 2 H 5 )(N(CH 3 ) 2 ) 3 ; hereinafter referred to as TAIMATA®; for additional details, see U.S. Pat. No. 6,593,484) and a reduction gas, The reduction gas can, for instance, include hydrogen or ammonia.  
      In an ALD process, the introduction of the first process gas material to processing chamber  10  comprises sequentially and alternatingly introducing the film precursor and the reduction gas. Alternatively, in a CVD process, the introduction of the first process gas material to processing chamber  10  comprises concurrent introduction of the film precursor and the reduction gas.  
      For instance, in thermal ALD, the film precursor is introduced to the processing chamber  10  to cause adsorption of the film precursor to exposed surfaces of substrate  25 . Preferably, a monolayer of material adsorbs to the exposed substrate surfaces. Thereafter, the reduction gas is introduced to processing chamber  10  to reduce the adsorbed film precursor in order to leave the desired film on substrate  25 . By elevating the substrate temperature, the film precursor thermally decomposes and chemically reacts with the reduction gas. The introduction of the film precursor and the reduction gas are repeated in order to produce a film of a desired thickness. A purge gas may be introduced between introduction of the film precursor and the reduction gas. The purge gas can include an inert gas, such as a noble gas (i.e., helium, neon, argon, xenon, krypton).  
      Next, as illustrated in  FIG. 5 , when performing the second deposition process, a second process gas material is introduced to the processing chamber. The second process gas material can be introduced concurrent with or immediately about the time in which the process space is increased in volume from V 1  to V 2 . The second process gas material includes a film precursor comprising tantalum, such as a metal halide (e.g., tantalum pentachloride) or a metal organic (e.g., Ta(NC(CH 3 ) 2 C 2 H 5 )(N(CH 3 ) 2 ) 3 ; hereinafter referred to as TAIMATA®; for additional details, see U.S. Pat. No. 6,593,484) and a reduction gas. The reduction gas can, for instance, include hydrogen or ammonia.  
      In a PEALD process, the introduction of the first process gas material to processing chamber  10  comprises sequentially and alternatingly introducing the film precursor and the reduction gas, while coupling power to processing chamber  10  to form plasma during the introduction of the reduction gas. Alternatively, in a PECVD process, the introduction of the first process gas material to processing chamber  10  comprises concurrent introduction of the film precursor and the reduction gas, while coupling power to processing chamber  10  to form plasma.  
      During plasma formation, power is coupled through, for example, the upper assembly  30  from the first power source  50  to the second process gas material. The coupling of power to the second process gas material heats the second process gas material, thus causing ionization and dissociation of the second process gas material (i.e., plasma formation) in order to form a deposit from the constituents of the second process gas material. As shown in  FIG. 5 , the processing chamber  10  can be purged with a purge gas for another period of time. The introduction of the first process gas material, the introduction of the second process gas material, and the formation of the plasma while the second process gas material is present can be repeated any number of times to produce a film of desired thickness.  
      In one example, a thermally-driven vapor deposition process, such as an ALD or CVD process, can be used during the first process described in  FIG. 5 . As such, tantalum (Ta), tantalum nitride, or tantalum carbonitride can be deposited using a thermally-driven ALD process, in which a Ta carrier such as TaF 5 , TaCl 5 , TaBr 5 , TaI 5 , Ta(CO) 5 , Ta[N(C 2 H 5 CH 3 )] 5  (PEMAT), Ta[N(CH 3 ) 2 ] 5  (PDMAT), Ta[N(C 2 H 5 ) 2 ] 5  (PDEAT), Ta(NC(CH 3 ) 3 )(N(C 2 H 5 ) 2 ) 3  (TBTDET), Ta(NC 2 H 5 )(N(C 2 H 5 ) 2 ) 3 , Ta(NC(CH 3 ) 2 C 2 H 5 )(N(CH 3 ) 2 ) 3 , or Ta(NC(CH 3 ) 3 )(N(CH 3 ) 2 ) 3 , absorbs of the surface of the substrate followed by a exposure to a reduction gas such as H 2 , NH 3 , N 2  and H 2 , N 2 H 4 , NH(CH 3 ) 2 , or N 2 H 3 CH 3 .  
      In another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing titanium (Ti), titanium nitride, or titanium carbonitride, the Ti carrier can include TiF 4 , TiCl 4 , TiBr 4 , TiI 4 , Ti[N(C 2 H 5 CH 3 )] 4  (TEMAT), Ti[N(CH 3 ) 2 ] 4  (TDMAT), or Ti[N(C 2 H 5 ) 2 ] 4  (TDEAT), and the reduction gas can include H 2 , NH 3 , N 2  and H 2 , N 2 H 4 , NH(CH 3 ) 2 , or N 2 H 3 CH 3 .  
      As another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing tungsten (W), tungsten nitride, or tungsten carbonitride, the W carrier can include WF 6 , or W(CO) 6 , and the reduction gas can include H 2 , NH 3 , N 2  and H 2 , N 2 H 4 , NH(CH 3 ) 2 , or N 2 H 3 CH 3 .  
      In another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing molybdenum (Mo), the Mo carrier can include molybdenum hexafluoride (MoF 6 ), and the reduction gas can include H 2 .  
      When depositing copper in a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , the Cu carrier can include Cu-containing organometallic compounds, such as Cu(TMVS)(hfac), also known by the trade name CupraSelect®, available from Schumacher, a unit of Air Products and Chemicals, Inc., 1969 Palomar Oaks Way, Carlsbad, Calif. 92009), or inorganic compounds, such as CuCl. The reduction gas can include at least one of H 2 , O 2 , N 2 , NH 3 , or H 2 O. As used herein, the term “at least one of A, B, C, . . . or X” refers to any one of the listed elements or any combination of more than one of the listed elements.  
      In another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing zirconium oxide, the Zr carrier can include Zr(NO 3 ) 4 , or ZrCl 4 , and the reduction gas can include H 2 O.  
      When depositing hafnium oxide in a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , the Hf carrier can include Hf(OBu t ) 4 , Hf(NO 3 ) 4 , or HfCl 4 , and the reduction gas can include H 2 O. In another example, when depositing hafnium (Hf), the Hf-carrier can include HfCl 4 , and the second process material can include H 2 .  
      In still another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing niobium (Nb), the Nb carrier can include niobium pentachloride (NbCl 5 ), and the reduction gas can include H 2 .  
      In another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing zinc (Zn), the Zn carrier can include zinc dichloride (ZnCl 2 ), and the reduction gas can include H 2 .  
      In another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing silicon oxide, the Si-carrier can include Si(OC 2 H 5 ) 4 , SiH 2 Cl 2 , SiCl 4 , or Si(NO 3 ) 4 , and the reduction gas can include H 2 O or O 2 . In another example, when depositing silicon nitride, the Si carrier can include SiCl 4 , or SiH 2 Cl 2 , and the reduction gas can include NH 3 , or N 2  and H 2 . In another example, when depositing TiN, the Ti carrier can include titanium nitrate (Ti(NO 3 )), and the reduction gas can include NH 3 .  
      In another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing aluminum, the Al carrier can include aluminum chloride (Al 2 Cl 6 ), or trimethylaluminum (Al(CH 3 ) 3 ), and the reduction gas can include H 2 . When depositing aluminum nitride, the Al carrier can include aluminum trichloride, or trimethylaluminum, and the reduction gas can include NH 3 , or N 2  and H 2 . In another example, when depositing aluminum oxide, the Al carrier can include aluminum chloride, or trimethylaluminum, and the reduction gas can include H 2 O, or O 2  and H 2 .  
      In another example of a thermally-driven vapor deposition process, such as an ALD or CVD process, for the first process shown in  FIG. 5 , when depositing GaN, the Ga carrier can include gallium nitrate (Ga(NO 3 ) 3 ), or trimethylgallium (Ga(CH 3 ) 3 ), and the reduction gas can include NH 3 .  
      In the examples given above for forming various material layers, the process material deposited for the first process shown in  FIG. 6  can include at least one of a metal film, a metal nitride film, a metal carbonitride film, a metal oxide film, or a metal silicate film. Meanwhile, the process material deposited for the second deposition process can include another material film of either the same or different metal composition. For example, the process material deposited for the first process shown in  FIG. 6  can include at least one of a tantalum film, a tantalum nitride film, or a tantalum carbonitride film. Meanwhile, the process material deposited for the second deposition process depicted in  FIG. 5  can include for example another tantalum film, another tantalum nitride film, or another tantalum carbonitride film (e.g., a tantalum film deposited over a tantalum carbonitride film). Alternatively, for example, the process material deposited for the second deposition process depicted in  FIG. 5  can include for example an Al film, or a Cu film deposited for example to metallize a via for connecting for example one metal line to another metal line or for connecting for example a metal line to source/drain contacts of a semiconductor device. The Al or Cu films can be formed with or without a plasma process using precursors for the Al and Cu as described above. Also, the process material deposited for the second deposition process depicted in  FIG. 5  can include a zirconium oxide film, a hafnium oxide film, a hafnium silicate film, a silicon oxide film, a silicon nitride film, a titanium nitride film, and/or a GaN film deposited to form an insulating layer such as for example above for a metal line or a gate structure of a semiconductor device.  
      Further, the first deposition process in  FIG. 5  need not occur by an ALD process but could according to the present invention occur using another thermal CVD process using suitable carrier gases known in the art. For example, silane and disilane could be used as silicon carriers for the deposition of silicon-based or silicon-including films. Germane could be used a germanium carrier for the deposition of germanium-based or germanium-including films. Such carriers could likewise be used during the plasma process depicted in  FIG. 5 . As such, the process material deposited for the first and second deposition process depicted in  FIG. 5  can include a metal silicide film and/or a germanium-including film deposited for example to form a conductive gate structure for a semiconductor device.  
      As illustrated in  FIG. 5 , following the deposition of the first film, the second film is deposited preferably with a plasma process. A plasma process such as a plasma enhanced chemical vapor deposition (PECVD) process or a plasma enhanced atomic layer deposition process is preferred for the deposition of the second film due to its typically higher growth rate compared to thermal CVD or thermal ALD, respectively. However, other techniques can be used according to the present invention to deposit the second film.  
      Furthermore, in the above alternating process illustrated in  FIG. 5 , the process volume can be varied between a first volume (V 1 ) during introduction of the first process gas material for the first time period and optionally the introduction of the purge gas for the second time period, and a second volume (V 2 ) during the introduction of the second process gas material for the third period of time and optionally the introduction of the purge gas for the fourth period of time. An optimal volume for V 1  and V 2  can be selected for the process space for each process step in the PEALD process.  
      For example, the first volume (V 1 ) can be sufficiently small such that the first process gas material passes through the process space and some fraction of the first process gas material adsorbs on the surface of the substrate. As the first volume of the process space is reduced, the amount of the first process gas material necessary for adsorption on the substrate surface is reduced and the time required to exchange the first process gas material within the first process space is reduced. For instance, as the first volume of the process space is reduced, the residence time is reduced, hence, permitting a reduction in the first period of time.  
      Moreover, for example, the second volume (V 2 ) can be set to a volume in which the formation of plasma from the second process material leads to the formation of uniform plasma above the substrate. The ability according to the present invention to be able to provide a plasma process geometry of comparable uniformity to the thermal process geometry permits the present invention to perform consecutive thermal and plasma processes in the same system without the need to transfer the process wafer between different processing systems, thereby saving process time and reducing surface contamination at the interfaces between the process films, leading to improved material properties for the resultant films.  
      In one embodiment of the present invention, the second volume V 2  of the process space defines a process space having an aspect ratio of height to width that is greater than 0.1 and preferably greater than 0.5. For example, as the aspect ratio decreases, the plasma uniformity has been observed to worsen, while as the aspect ratio increases, the plasma uniformity has been observed to improve.  
      When processing substrates including semiconductor wafers, the process space is substantially cylindrical, characterized by a diameter and a height or spacing between the substrate and the upper assembly. The diameter is related to the size of the substrate, whereas the spacing (or height) can be the variable parameter for adjusting the volume of the process space. The first volume during introduction of the first process material can, for example, include a spacing less than or equal to 20 mm from the substrate stage  20  to the upper assembly  30 , and the second volume during introduction of the second process material can, for example, include a spacing greater than 20 mm.  
       FIG. 6  shows a process flow diagram of a process in accordance with one embodiment of the present invention. The process of  FIG. 6  may be performed by the processing system of  FIGS. 1-4 , or any other suitable processing system. As seen in  FIG. 6 , in step  610 , the process begins when a substrate is disposed in a vapor deposition system having a process space defined above the substrate. In step  620 , a first process gas composition is introduced to the process space according to a first vapor deposition process. In step  630 , a first film is deposited on the substrate. In step  640 , a second process gas composition is introduced into a second process space different in size from the first process space. In step  650 , a second film is deposited on the substrate from the second process gas composition.  
      In steps  630  and  650 , the material deposited for the first and second films can be the same material or can be different materials.  
      In step  610 , the vapor deposition system can be configured for at least one of an atomic layer deposition (ALD) process, a plasma enhanced ALD (PEALD) process, a plasma enhanced chemical vapor deposition (PECVD) process, or a thermal chemical vapor deposition (CVD) process. As such, the first film deposited can be deposited with the ALD process, and the second film can be deposited with the PEALD process. Alternatively, the first film deposited can be deposited with the thermal CVD process, and the second film can be deposited with the PECVD process. Alternatively, the first film deposited can be deposited with the ALD process, and the second film can be deposited with the thermal CVD process or the PECVD process.  
      In step  620 , the first process gas composition is introduced in the process space above the substrate surrounded by a shield. In one embodiment of the present invention, the shield can be perforated permitting pumping of the first process gas composition through the shield. If the shield does not have perforations, the interior of the process space can be pumped separately.  
      In step  650 , a substrate stage holding the substrate can be translated to a position that improves the uniformity of deposit of the second film. In step  650 , a plasma can be formed by applying RF energy at a frequency from 0.1 to 100 MHz. In one aspect of the present invention, prior to forming the plasma, the volume of the process space is increased in order to facilitate conditions more conducive for plasma uniformity. As such, prior to step  650 , the substrate stage can be translated to a position that improves plasma uniformity of the second vapor deposition process. For example, the substrate stage can be set to a position in which the plasma uniformity is better than 2% across a 200 mm diameter of the substrate stage or better than 1% across a 200 mm diameter of the substrate stage.  
      During step  650 , a substrate bias can be provided to the substrate. For example, the substrate bias can be a DC voltage and/or a RF voltage having a frequency from 0.1 to 100 MHz. Prior to step  650 , electromagnetic power can be coupled to the vapor deposition system to generate a plasma that accelerates a reduction reaction process at a surface of the first film.  
      Furthermore, a purge gas can be introduced after depositing the first film. Moreover, with or without the purge gas present, electromagnetic power can be coupled to the vapor deposition system to release contaminants from at least one of the vapor deposition system or the substrate. The electromagnetic power can be coupled into the vapor deposition system in the form of a plasma, an ultraviolet light, or a laser.  
      In one embodiment of the present invention the purge gas can be a reactive cleaning gas. In this case, the reactive cleaning gas chemically reacts with contaminants on the process chamber walls and/or the substrate surface to assist in removing such impurities from the process chamber. As would be understood by one of ordinary skill in the art, the composition of the reactive gas depends largely on the ALD process and, in particular, the contaminants to be removed from the process chamber. That is, a reactive gas is selected to react with the contaminants to be removed from the process chamber. In considering an example of depositing a tantalum film, using tantalum pentachloride as the first process material and hydrogen for the second process material (i.e., reduction reaction), chlorine contaminants may reside on the processing walls and within the deposited film itself. To remove these chlorine contaminants, ammonia (NH 3 ) can be introduced to chemically react with the chlorine contaminants and release them from the walls and/or substrate, so that the contaminants can be expelled from the chamber by vacuum pumping.  
      In another embodiment of the present invention, the process chamber walls may be heated in order to facilitate a chemical reaction to remove the contaminants. For example, when reducing chlorine contaminants as described above, the chamber walls are heated to at least 80° C.  
      As shown in  FIGS. 1-4 , deposition systems  1  and  1 ′ include a controller  70  that can be coupled to processing chamber  10 , substrate stage  20 , upper assembly  30 , first process material supply system  40 , second process material supply system  42 , purge gas supply system  44 , first power source  50 , substrate temperature control system  60 , and/or process volume adjustment system  80 .  
      The controller  70  can include a microprocessor, memory, and a digital I/O port capable of generating control voltages sufficient to communicate and activate inputs to deposition system  1  ( 1 ′) as well as monitor outputs from deposition system  1  ( 1 ′) in order to control and monitor the above-discussed processes for film deposition. For example, the controller  70  can include computer readable medium containing program instructions for execution to accomplish the steps described above in relation to  FIG. 6 . Moreover, the controller  70  may be coupled to and may exchange information with the process chamber  10 , substrate stage  20 , upper assembly  30 , first process material gas supply system  40 , second process material supply gas system  42 , purge gas supply system  44 , first power source  50 , second power source  52 , substrate temperature controller  60 , and/or pressure control system  32 . For example, a program stored in the memory may be utilized to activate the inputs to the aforementioned components of the deposition system  1  ( 1 ′) according to a process recipe in order to perform one of the above-described non-plasma or plasma enhanced deposition processes.  
      One example of the controller  70  is a DELL PRECISION WORKSTATION 610™, available from Dell Corporation, Austin, Tex. However, the controller  70  may be implemented as a general-purpose computer system that performs a portion or all of the microprocessor based processing steps of the invention in response to a processor executing one or more sequences of one or more instructions contained in a memory. Such instructions may be read into the controller memory from another computer readable medium, such as a hard disk or a removable media drive. One or more processors in a multi-processing arrangement may also be employed as the controller microprocessor to execute the sequences of instructions contained in main memory. In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, embodiments are not limited to any specific combination of hardware circuitry and software.  
      The controller  70  includes at least one computer readable medium or memory, such as the controller memory, for holding instructions programmed according to the teachings of the invention and for containing data structures, tables, records, or other data that may be necessary to implement the present invention. Examples of computer readable media are compact discs, hard disks, floppy disks, tape, magneto-optical disks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM, SDRAM, or any other magnetic medium, compact discs (e.g., CD-ROM), or any other optical medium, punch cards, paper tape, or other physical medium with patterns of holes, a carrier wave (described below), or any other medium from which a computer can read.  
      Stored on any one or on a combination of computer readable media, the present invention includes software for controlling the controller  70 , for driving a device or devices for implementing the invention, and/or for enabling the controller to interact with a human user. Such software may include, but is not limited to, device drivers, operating systems, development tools, and applications software. Such computer readable media further includes the computer program product of the present invention for performing all or a portion (if processing is distributed) of the processing performed in implementing the invention.  
      The computer code devices of the present invention may be any interpretable or executable code mechanism, including but not limited to scripts, interpretable programs, dynamic link libraries (DLLs), Java classes, and complete executable programs. Moreover, parts of the processing of the present invention may be distributed for better performance, reliability, and/or cost.  
      The term “computer readable medium” as used herein refers to any medium that participates in providing instructions to the processor of the controller  70  for execution. A computer readable medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical, magnetic disks, and magneto-optical disks, such as the hard disk or the removable media drive. Volatile media includes dynamic memory, such as the main memory. Moreover, various forms of computer readable media may be involved in carrying out one or more sequences of one or more instructions to the processor of the controller for execution. For example, the instructions may initially be carried on a magnetic disk of a remote computer. The remote computer can load the instructions for implementing all or a portion of the present invention remotely into a dynamic memory and send the instructions over a network to the controller  70 .  
      The controller  70  may be locally located relative to the deposition system  1  ( 1 ′), or it may be remotely located relative to the deposition system  1  ( 1 ′). For example, the controller  70  may exchange data with the deposition system  1  ( 1 ′) using at least one of a direct connection, an intranet, the Internet and a wireless connection. The controller  70  may be coupled to an intranet at, for example, a customer site (i.e., a device maker, etc.), or it may be coupled to an intranet at, for example, a vendor site (i.e., an equipment manufacturer). Additionally, for example, the controller  70  may be coupled to the Internet. Furthermore, another computer (i.e., controller, server, etc.) may access, for example, the controller  70  to exchange data via at least one of a direct connection, an intranet, and the Internet. As also would be appreciated by those skilled in the art, the controller  70  may exchange data with the deposition system  1  ( 1 ′) via a wireless connection.  
      Although only certain exemplary embodiments of inventions have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention.