Filling high aspect ratio features on substrates

Abstract

A system includes a pedestal and a controller. The pedestal includes a base portion and a plurality of pockets located around a periphery of the base portion. The pockets include slots configured to receive a carrier ring carrying a substrate. The substrate partially extends over the slots in the pockets. The pedestal includes a plenum defined in the base portion. The plenum includes angular holes opening into the slots in the pockets. The controller is configured to deposit an inhibitor controlled enhanced (ICE) layer on a top surface of the substrate; and to supply, after depositing the ICE layer, a gas through the angular holes to areas on a bottom surface of the substrate that lie above the slots.

Description

Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POAFILLING HIGH ASPECT RATIO FEATURES ON SUBSTRATESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 683,047, filed on August 14, 2024, which is related to International Application No. PCT / US2023 / 027063 filed on July 7, 2023. The entire disclosures of the above applications are incorporated herein by reference.FIELD

[0002] The present disclosure relates generally to substrate processing systems and more particularly to filling high aspect ratio features on substrates.BACKGROUND

[0003] The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0004] Broadly speaking, a substrate processing system (also called a tool) typically comprises a plurality of processing chambers (also called stations) in which processes such as deposition, etching, and other treatments are performed on substrates such as semiconductor wafers. Examples of processes that may be performed on a substrate comprise a chemical vapor deposition (CVD) process, a thermal CDV process, a plasma enhanced chemical vapor deposition (PECVD) process, a chemically enhanced plasma vapor deposition (CEPVD) process, a sputtering physical vapor deposition (PVD) process, atomic layer deposition (ALD), and plasma enhanced ALD (PEALD). Additional examples of processes that may be performed on a substrate comprise etching (e.g., chemical etching, plasma etching, reactive ion etching, etc.) and cleaning processes.

[0005] During processing, a substrate is arranged on a substrate support such as a pedestal in a station. During deposition, gas mixtures comprising one or more precursors are introduced into the station, and plasma may be optionally struck to activate chemical reactions. During etching, gas mixtures comprising etch gases areAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA introduced into the station, and plasma may be optionally struck to activate chemical reactions. A computer-controlled robot typically transfers substrates from one station to another in a sequence in which the substrates are to be processed.

[0006] In ALD, a gaseous chemical process sequentially deposits a thin film on a surface of a material (e.g., a surface of a substrate such as a semiconductor wafer). Most ALD reactions use at least two chemicals called precursors (reactants) that react with the surface of the material one precursor at a time in a sequential, self-limiting manner. Through repeated exposure to separate precursors, a thin film is gradually deposited on the surface of the material. Thermal ALD (T-ALD) is carried out in a heated station. The station is maintained at a sub-atmospheric pressure using a vacuum pump and a controlled flow of an inert gas. The substrate to be coated with an ALD film is placed in the station and is allowed to equilibrate with the temperature of the station before starting the ALD process.SUMMARY

[0007] A system comprises a pedestal and a controller. The pedestal comprises a base portion and a plurality of pockets located around a periphery of the base portion. The pockets comprise slots configured to receive a carrier ring carrying a substrate. The substrate partially extends over the slots in the pockets. The pedestal comprises a plenum defined in the base portion. The plenum comprises angular holes opening into the slots in the pockets. The controller is configured to deposit an inhibitor controlled enhanced (ICE) layer on a top surface of the substrate; and to supply, after depositing the ICE layer, a gas through the angular holes to areas on a bottom surface of the substrate that lie above the slots.

[0008] In additional features, the controller is configured to raise the carrier ring above the base portion to a height selected to form a gap between the substrate and the carrier ring through which the gas flows to the areas on the bottom surface of the substrate without flowing over the top surface of the substrate. The controller is configured to select a duration and at least one of a flow rate and a pressure for supplying the gas to the areas on the bottom surface of the substrate to remove a film deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA

[0009] In additional features, the system further comprises a showerhead configured to supply a mixture of ammonia and tungsten hexafluoride to deposit the ICE layer on the top surface of the substrate. The deposition of the ICE layer on the top surface of the substrate deposits a film of tungsten nitride on the areas on the bottom surface of the substrate. The controller is configured to supply hydrogen as the gas to the areas on the bottom surface of the substrate to reduce the film of tungsten nitride deposited on the areas on the bottom surface of the substrate.

[0010] In still other features, a method comprises depositing an inhibitor controlled enhanced (ICE) layer on a top surface of a substrate arranged on a pedestal. The deposition of the ICE layer on the top surface of the substrate deposits a film on areas on a bottom surface of the substrate. The method comprises supplying, after depositing the ICE layer, a gas through the pedestal to the areas on the bottom surface of the substrate to remove the film deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.

[0011] In additional features, the method further comprises, after depositing the ICE layer and before supplying the gas: adjusting a height of a carrier ring used to transport the substrate to form a gap between the substrate and the carrier ring through which the gas flows to the areas on the bottom surface of the substrate without flowing over the top surface of the substrate; and selecting a duration and at least one of a flow rate and a pressure at which the gas is supplied to the areas on the bottom surface of the substrate to remove the film deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.

[0012] In additional features, depositing the ICE layer comprises supplying a mixture of ammonia and tungsten hexafluoride from a showerhead to the substrate arranged on the pedestal, the mixture forming the film comprising tungsten nitride on the areas on the bottom surface of the substrate that are exposed to the mixture. Supplying the gas comprises supplying hydrogen through the pedestal to the areas on the bottom surface of the substrate to reduce the film comprising tungsten nitride deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.

[0013] In additional features, the method further comprises depositing, before depositing the ICE layer, a seed layer of tungsten in a feature on the top surface of the substrate. The method further comprises depositing the ICE layer in the feature afterAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA depositing the seed layer. The deposition of the ICE layer deposits the film of tungsten nitride on the areas on the bottom surface of the substrate. The method further comprises reducing, after depositing the ICE layer, the film of tungsten nitride by supplying the gas, the gas being hydrogen. The method further comprises depositing tungsten in the feature after the reduction of the film of tungsten nitride.

[0014] In additional features, the method further comprises depositing the seed layer using atomic layer deposition, and depositing tungsten in the feature using chemical vapor disposition.

[0015] In additional features, the method further comprises depositing the seed layer in a first station by supplying a mixture of tungsten hexafluoride and diborane to the first station. The method further comprises depositing the ICE layer in a second station by supplying a mixture of ammonia and tungsten hexafluoride to the second station. The method further comprises reducing the film of tungsten nitride by supplying the gas to the second station. The method further comprises depositing tungsten in the feature in a third station by supplying a mixture of tungsten hexafluoride and hydrogen to the third station.

[0016] In still other features, a method of filling a feature on a substrate with tungsten comprises depositing, in a first station, a seed layer of tungsten in the feature using atomic layer deposition by supplying a mixture of tungsten hexafluoride and diborane through a first showerhead in the first station. The method comprises depositing, in a second station, after depositing the seed layer, an inhibitor controlled enhanced (ICE) layer in the feature by supplying a mixture of ammonia and tungsten hexafluoride through a second showerhead in the second station. The deposition of the ICE layer deposits a film of tungsten nitride on areas on a bottom surface of the substrate. The method comprises reducing, in the second station, after depositing the ICE layer, the film of tungsten nitride by supplying hydrogen to the second station. The method comprises depositing, in a third station, after the reducing of the film of tungsten nitride, tungsten in the feature using chemical vapor deposition by supplying a mixture of tungsten hexafluoride and hydrogen through a third showerhead in the third station.

[0017] In additional features, the method further comprises supplying an inert gas through pedestals in the first, second, and third stations during the atomic layer deposition, deposition of the ICE layer, and the chemical vapor deposition, The methodAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA further comprises supplying only hydrogen through the pedestal in the second station during the reduction of the film of tungsten nitride.

[0018] In additional features, the method further comprises, after depositing the ICE layer and before the reduction of the film of tungsten nitride: adjusting, in the second station, a height of a carrier ring used to transport the substrate between the first, second, and third stations to form a gap between the substrate and the carrier ring through which hydrogen flows without flowing over the feature; and selecting a duration and at least one of a flow rate and a pressure at which hydrogen is supplied to remove the film of tungsten nitride from the areas on the bottom surface of the substrate.

[0019] In still other features, a system comprises a first station to perform a first process on a substrate, the first station comprising a first showerhead and a first pedestal. The system comprises a second station to perform a second process on the substrate, the second station comprising a second showerhead and a second pedestal. The system comprises a third station to perform a third process on the substrate, the third station comprising a third showerhead and a third pedestal. Each of the first, second, and third pedestals comprises a base portion. The base portion comprises a plurality of pockets located around a periphery of the base portion. The pockets comprise slots configured to receive a carrier ring carrying the substrate. The substrate partially extends over the slots in the pockets. The base portion comprises a pocket gas plenum defined in the base portion. The pocket gas plenum comprises angular holes opening into the slots in the pockets. The system comprises a controller. The controller is configured to deposit, in the first station, a seed layer of tungsten on a top surface of the substrate using the first process by supplying a mixture of tungsten hexafluoride and diborane through the first showerhead. The controller is configured to deposit, in the second station, after depositing the seed layer, an inhibitor controlled enhanced (ICE) layer on the top surface of the substrate using the second process by supplying a mixture of ammonia and tungsten hexafluoride through the second showerhead. The deposition of the ICE layer deposits tungsten nitride on areas on a bottom surface of the substrate that lie above the slots in the pockets. The controller is configured to reduce, in the second station, after depositing the ICE layer, the tungsten nitride from the areas on the bottom surface of the substrate by supplying hydrogen through the pocket gas plenum and the angular holes in the second pedestal to the slots in the pockets. The controller is configured to deposit, in the third station, after reducing the tungsten nitride from the areas on the bottom surface of the substrate, tungsten on theAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA top surface of the substrate using the third process by supplying a mixture of tungsten hexafluoride and hydrogen through the third showerhead.

[0020] In additional features, the controller is configured to supply, during the first, second, and third processes, an inert gas through a plenum in the first, second, and third pedestals that is different than the pocket gas plenum and the angular holes. The controller is configured to supply only hydrogen through the pocket gas plenum and the angular holes in the second pedestal to the slots in the pockets during the reduction of the tungsten nitride from the areas on the bottom surface of the substrate.

[0021] In additional features, the controller is configured to, after depositing the ICE layer and before the reduction of the tungsten nitride from the areas on the bottom surface of the substrate: adjust, in the second station, a height of the carrier ring used to transport the substrate between the first, second, and third stations to form a gap between the substrate and the carrier ring through which hydrogen flows to the slots in the pockets without flowing over the top surface of the substrate; and select a duration and at least one of a flow rate and a pressure at which hydrogen is supplied to the slots in the pockets to reduce the tungsten nitride from the areas on the bottom surface of the substrate.

[0022] In additional features, the first process is atomic layer deposition, and the third process is chemical vapor deposition.

[0023] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims, and the drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

[0025] FIG. 1 schematically shows an example of a substrate processing tool (tool) comprising multiple stations for processing a substrate according to the present disclosure;

[0026] FIG. 2 shows an example of a substrate processing system comprising a station of the tool of FIG. 1 for processing the substrate according to the present disclosure;Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA

[0027] FIG. 3 shows an example of a pedestal used in the station of FIG. 2 for processing the substrate according to the present disclosure;

[0028] FIG. 4 shows an example of a top view of the pedestal of FIG. 3;

[0029] FIG. 5 shows an example of a backside of a substrate with deposition typically occurring above pocket areas of the pedestal of FIG. 3 during filling high-aspect ratio features on the substrate;

[0030] FIG. 6 shows an example of supplying a gas to pocket areas of the pedestal of FIG. 3 with a carrier ring pulled down close to the pedestal during filling high-aspect ratio features on the substrate;

[0031] FIG. 7 shows an example of supplying the gas to the pocket areas of the pedestal of FIG. 3 with the carrier ring raised relative to the pedestal during filling high- aspect ratio features on the substrate according to the present disclosure;

[0032] FIG. 8 shows an example of a cross-sectional view of the pedestal of FIG. 3; and

[0033] FIG. 9 shows an example of a method of filling high-aspect ratio features on the substrate according to the present disclosure.

[0034] In the drawings, reference numbers may be reused to identify similar and / or identical elements.DETAILED DESCRIPTION

[0035] Contacts are three-dimensional structures on a substrate with a gap that is filled with a conductive material such as tungsten. The structure is typically sandwiched between oxide / nitride layer and a barrier layer (e.g., titanium nitride) on the substrate. In some tools, multiple process modules, which are also called stations, (e.g., quad station modules or QSMs) are used to treat a substrate using different processes to provide contacts (e.g., features filled with tungsten) on the substrate. The QSMs integrate different steps used to fill tungsten in high aspect ratio contacts (also called high aspect ratio features) on the substrate.

[0036] The steps to fill tungsten in high aspect ratio features on a substrate typically include a nucleation and low fluorine tungsten (LFW) deposition step (e.g., called a nucleation step performed using atomic layer deposition or ALD), an inhibitor controlled enhanced (ICE) layer deposition step (called an ICE step), and chemical vaporAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA deposition (CVD) of tungsten (called a CVD step). The three steps are generally called deposition-ICE-deposition (DID) steps and are performed sequentially (the sequence being nucleation, ICE, and CVD) in different stations.

[0037] The first nucleation step is performed in a first station to deposit a seed layer of tungsten on the features by supplying tungsten hexafluoride (WFe) and diborane (B2H6) to a heated substrate. The seed layer of tungsten facilitates the subsequent tungsten deposition (fill) performed in the last CVD step. After the first nucleation step, the second ICE step is performed on the substrate in a second station to selectively deposit tungsten nitride on portions of the features to be filled with tungsten. The ICE step includes heating the substrate and supplying pulses of ammonia (NH3) and tungsten hexafluoride (WFe), which react with each other forming tungsten nitride. Thereafter, the third CVD step is performed in a third station to deposit tungsten in the features (i.e., the features are filled with tungsten) using CVD. In the CVD step, WFe and hydrogen are supplied to the heated substrate. During the CVD step, tungsten growth first occurs on the bottom of the feature since the tungsten nitride on the top of feature inhibits the tungsten growth on the top of the feature. After some time delay, the CVD growth starts on the middle to the top of the feature. During one or more of the DID steps, a backside purge gas (e.g., an inert gas such as Ar) is supplied to minimize deposition of materials on the backside of the substrate.

[0038] Some substrate supports (also called pedestals) comprise pockets around a periphery of the pedestal. A carrier ring comprising support assemblies (also called fingers) is used to transport substrates between different stations to perform the different DID steps. The fingers extend radially inwards from under the carrier ring and support the substrate on inner ends of the fingers during transport. The pockets in the pedestal comprise slots. The slots support the fingers when the carrier ring carrying the substrate on the inner ends of the fingers is lowered and the substrate is placed on the pedestal for processing. To transport the substrate after processing, the carrier ring is lifted by an index spindle, the substrate is picked by the fingers, and a robot transports the carrier ring with the substrate to another station for further processing (e.g., to perform a next step).

[0039] The slots in the pockets extend radially inwards into an area of the pedestal on which the substrate rests during processing. An outer diameter (OD) of the substrate exceeds a diameter of a circle on which inner ends of the slots lie. Accordingly, portionsAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA of the backside of the substrate that lie above the pockets are exposed to process chemistries (e.g., NH3 and WFe) used during the ICE step. Consequently, some amount of tungsten nitride is formed on the portions of the backside of the substrate that lie above the pockets. For brevity, the portions of the substrate that lie above the pockets are generally called pocket areas of the substrate.

[0040] Due to the tungsten nitride formed on the portions of the backside of the substrate that lie above the pockets, during the subsequent CVD step, the tungsten deposited on the pocket areas of the substrate (i.e., on the top surface of the substrate above the pocket areas) has a lower thickness than the rest of the substrate. Due to the lower thickness of the tungsten deposited on the pocket areas of the substrate, a parameter called within wafer non-uniformity (WiW NU) of the full stack of layers deposited on the substrate using the DID steps also increases. The lower thickness of the tungsten deposited on the pocket areas of the substrate adversely impacts the WiW NU and the thickness range of tungsten deposited on the substrate.

[0041] Some solutions improve the thickness of the tungsten deposited on the pocket areas of the substrate but with only with limited success. For example, the carrier ring can be redesigned to have additional cutoff portions around the pocket areas. The additional cutoff portions allow more backside purge gas (e.g., Ar) to flow and push away more of the material such as NH3 and WFe from the pocket areas during the ICE step. However, this design change also impacts the subsequent tungsten deposition by CVD, which results in non-uniform tungsten deposition on the pocket areas of the substrate. Other approaches include supplying additional backside purge gas (e.g., Ar) from the pedestal during the ICE step. However, this approach is not effective for all process conditions.

[0042] The present disclosure solves the above problems using a new approach that mitigates the low tungsten thickness in the pocket areas of the substrate. Specifically, the new approach comprises supplying backside hydrogen (H2) after the ICE step and before the CVD step in an additional step called a post-ICE soak step. Using this approach, the tungsten thickness in the pocket areas as well as the overall WiW NU of the substrate are highly improved.

[0043] Specifically, the solution of the present disclosure comprises inserting (adding) a post-ICE soak step by supplying backside hydrogen (H2) after the ICE step and before the CVD step (i.e., between the ICE and CVD steps). During the post-ICE soakAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA step, backside H2 is only introduced to the pocket areas through a pocket purge gas line in the pedestal (described below). The backside H2 is able to de-ICE (remove) the unnecessarily deposited ICE film on the backside of the substrate above the pockets in the ICE step. Specifically, the backside H2 reduces (as in a chemical reaction called reduction) the tungsten nitride that was formed during the ICE step on the portions of the backside of the substrate that lie above the pockets. Thus, the subsequent tungsten deposition by CVD is not impacted by the ICE step. By adjusting wafer-to-ring gap (WRG) between the substrate and the carrier ring, tuning the flow rate of the backside H2, and the soak time (i.e., the duration of the post-ICE soak step), the tungsten thickness in the pocket areas as well as the overall WiW NU of the substrate are highly improved.

[0044] Unlike other solutions, the solution of the present disclosure works well in different process conditions, where the other approaches do not work effectively as described above. In the solution of the present disclosure, although the new step (i.e., the post-ICE soak step) is added (inserted into the DID sequence), the wafer throughput is not impacted because the ICE step can be performed without waiting after the substrate is transferred to the station in which the ICE step is performed. The wait time before the ICE step can be avoided or reduced to accommodate the subsequent post-ICE soak step to keep the overall timing of the DID steps unchanged. Thus, the solution of the present disclosure maximizes the technical benefits (tungsten thickness in the pocket areas and WiW NU of the substrate) without impacting productivity.

[0045] The present disclosure is organized as follows. An example of a tool comprising a quad-station module (QSM) in which the deposition-ICE-deposition (DID) steps with the added post-ICE soak step are performed is shown and described with reference to FIG. 1 . An example of a station of the QSM along with other subsystems of the tool is shown and described with reference to FIG. 2. An example of a pedestal used to perform the DID steps and the post-ICE soak step in the stations of the tool is shown and described with reference to FIG. 3. A top view of the pedestal is shown and described with reference to FIG. 4. An example of a backside of a substrate with deposition typically occurring in the pocket areas of the substrate without the post-ICE soak step is shown and described with reference to FIG. 5. Examples of the post-ICE soak step and the wafer-to-ring gap (WRG) adjustment are shown and described with reference to FIGS. 6 and 7. An example of a cross-sectional view of the pedestal usedAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA to perform the DID steps and the post-ICE soak step is shown and described with reference to FIG. 8. An example of a method of filling high-aspect ratio features by performing the DID steps and the post-ICE soak step is shown and described with reference to FIG. 9.EXAMPLES OF TOOL AND STATION

[0046] FIG. 1 schematically shows an example of a substrate processing tool (tool) 10. For example, the tool 10 comprises four (or any number of) stations: a first station 12, a second station 14, a third station 16, and a fourth station 18. The four stations are collectively called a quad station module (QSM). For example, each of the stations 12, 14, 16, and 18 may be configured to perform one or more processes on a substrate for filling high-aspect ratio features on the substrate according to the present disclosure. Examples of the processes comprise ALD for the nucleation step, inhibitor controlled enhanced (ICE) layer deposition for the ICE step, a post-ICE soak process for the post- ICE soak step, and CVD for the CVD step.

[0047] Depending on the processes performed on the substrate in each station, an index spindle operates a transfer robot (collectively shown at 20) to transfer the substrate between the stations 12, 14, 16, and 18 using a carrier ring (shown at 125 in FIG. 2). For example, the transfer robot 20 loads the substrate using the carrier ring in the first station 12 where the nucleation step is performed on the substrate using ALD. Subsequently, the transfer robot 20 transfers the substrate using the carrier ring from the first station 12 to the second station 14 where the ICE step and the post-ICE soak step are performed on the substrate. Subsequently, the transfer robot 20 transfers the substrate using the carrier ring from the second station 14 to the third station 16 where the CVD step is performed on the substrate. Subsequently, the transfer robot 20 may transfer the substrate using the carrier ring from the third station 16 to the fourth station 18 for further processing.

[0048] FIG. 2 shows an example of a substrate processing system 100 and a station 112 in which a substrate 124 is processed according to the present disclosure as described below in detail. The station 112 is representative of the stations 12-18 shown in FIG. 1 and may be any of the stations 12-18 of the tool 10. The station 112 comprises a pedestal 114 and a showerhead 116. An example of the pedestal 114 is shown and described in further detail with reference to subsequent figures. The post- ICE soak step can be performed along with the DID steps using many other pedestalsAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA that comprise a pocket gas plenum 466 and angular holes 462 (both shown in FIG. 8). Examples of such other pedestals are shown and described in International Application No. PCT / US23 / 27063 filed on July 7, 2023, which is incorporated by reference in its entirety.

[0049] The substrate processing system 100 comprises a gas delivery system 150. The gas delivery system 150 provides the gases and gas mixtures needed to perform the DID steps and the post-ICE soak step on the substrate 124 in the respective stations. While all the gases, including a vaporized precursor delivery system 151 , are shown together with a single station 112, only the necessary gases can be supplied to each of the stations as needed to perform the respective steps on the substrate 124 as described below in detail.

[0050] For example, a mixture of process gases such as tungsten hexafluoride (WFe) and diborane (B2H6) is supplied to the showerhead 116 and an inert purge gas such as argon is supplied to the pedestal 114 only in the station in which the nucleation step is performed. A mixture of process gases such as ammonia (NH3) and WFe is supplied to the showerhead 116 and an inert purge gas such as argon is supplied to the pedestal 114 only in the station in which the ICE step is performed, which is followed by supplying only hydrogen to the pocket areas of the pedestal 114 during the post-ICE soak step performed in the same station. A mixture of process gases such as vaporized precursor WFe mixed with hydrogen is supplied to the showerhead 116 and an inert purge gas such as argon is supplied to the pedestal 114 only in the station in which the CVD step is performed.

[0051] Accordingly, while only one station 112 is shown as an example, the substrate processing system 100 may comprise a plurality of stations 112. Each station 112 may use the pedestal 114 described below. The substrate 124 may be processed sequentially in the stations 112 to perform the DID steps and the posit-ICE soak step as described below. Different processes such as atomic layer deposition (ALD), inhibitor controlled enhanced (ICE) layer deposition and the post-ICE soak process, and chemical vapor deposition (CVD) may be performed on the substrate 124 in different stations 112 as described below.

[0052] Further, the substrate processing system 100 may comprise a radio frequency (RF) power supply 160. If plasma is used during the processing of the substrate 124 (e.g., during any of the DID steps), the RF power supply 160 may supply RF power toAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA the showerhead 116 to strike plasma. However, if plasma is not used during the processing of the substrate 124 (e.g., during any of the DID steps), the power supply 160 may be omitted or turned off. For example, the CVD step uses a thermal CVD process in which plasma is not used. Accordingly, the station 112 in which the CVD step is performed, the power supply 160 may be omitted or turned off.

[0053] The pedestal 114 comprises a base portion 118 and a stem portion 120. The stem portion 120 extends from base portion 118 and is coupled to the bottom of the station 112. During processing, the transfer robot 20 transfers the substrate 124 carried on the carrier ring 125 into the station 112. The index spindle lowers the carrier ring 125, which rests in the pockets of the pedestal 114 as described below, and the substrate 124 is placed on (and clamped to) a top surface of the base portion 118 of the pedestal 114 for processing.

[0054] The showerhead 116 comprises a base portion 126 and a stem portion 128. The base portion 126 of the showerhead 116 is cylindrical. The stem portion 128 of the showerhead 116 extends from the base portion 126 of the showerhead 116. The stem portion 128 of the showerhead 116 is attached to a top plate of the station 112. The stem portion 128 of the showerhead 116 receives various gases (e.g., process gases, vaporized precursors, purge gases, etc.) from the gas delivery system 150 via a manifold 152. In each station 112, depending on the process being performed on the substrate 124 (e.g., the DID steps including the post-ICE soak step), the gas delivery system 150 supplies different gases to the showerhead 116 and the pedestal 114 as described below. The base portion 126 of the showerhead 116 comprises a faceplate comprising through holes or slots (not shown) through which the gases are introduced into the station 112. The base portion 118 of the pedestal 114 comprises different plenums, grooves, and holes to clamp the substrate 124 to the pedestal 114 and to supply different gases during different processes performed on the substrate 124 (e.g., the DID steps including the post-ICE soak step).

[0055] For example, in the station 112 in which the nucleation step is performed on the substrate 124 using ALD, the gas delivery system 150 supplies a mixture of tungsten hexafluoride (WFe) and diborane (B2H6) to the showerhead 116 of that station 112 and supplies an inert purge gas such as argon to the pedestal 114 of that station 112 during the ALD process performed on the substrate 124 in that station 112. Subsequently, in another station 112 in which the ICE step is performed on the substrate 124, the gasAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA delivery system 150 supplies a mixture of ammonia (NH3) and WFe to the showerhead 116 of that station 112 and supplies an inert purge gas such as argon to the pedestal 114 of that station 112 during an ICE layer deposition process performed on the substrate 124 in that station 112. In the same station 112 in which the ICE step is performed, following the ICE step, the gas delivery system 150 supplies only hydrogen to the pocket areas of the pedestal 114 of that same station 112 during the post-ICE soak step performed on the substrate 124 in that same station 112. No other gases are supplied to the showerhead 116 and the pedestal 114 during the post-ICE soak step performed on the substrate 124. Subsequently, in another station 112 in which the CVD step is performed on the substrate 124, the gas delivery system 150 supplies a mixture of vaporized precursor WFe and hydrogen to the showerhead 116 of that station 112 and supplies an inert purge gas such as argon to the pedestal 114 of that station 112 during a CVD process performed on the substrate 124 in that station 112.

[0056] The gas delivery system 150 comprises gas sources 154, valves 156, and mass flow controllers (MFCs) 158. The gas sources 154 supply various gases such as the process gases and purge gases described above. The valves 156 are connected to the gas sources 154 and can be controlled to supply the gases to the MFCs 158. The MFCs 158 regulate the flow of gases to the manifold 152. Additionally, the vaporized precursor delivery system 151 delivers one or more vaporized precursors via respective valves (not shown) to the manifold 152. The manifold 152 supplies the gases and / or gas mixtures to the showerhead 116 as described above.

[0057] The base portion 118 of the pedestal 114 comprises a heater 162. The heater 162 heats the base portion 118 of the pedestal 114, which in turn heats the substrate 124 during the DID steps and the post-ICE soak step. The base portion 118 of the pedestal 114 comprises a temperature sensor 164 (e.g., a thermocouple) to sense the temperature of the pedestal 114.

[0058] The base portion 126 of the showerhead 116 may also comprise a heater (not shown) to heat the gases being introduced into the station 112. Additionally, the base portion 126 of the showerhead 1216 may also comprise a temperature sensor 168 to sense the temperature of the showerhead 116.

[0059] The substrate processing system 100 comprises additional valves 190 connected to the gas sources 154, and comprises additional MFCs and a pressure controller collectively shown at 192. During the DID steps, an inert purge gas such asAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA argon from one of the gas sources 154 is introduced into the pedestal 114 via the valves 190 through a purge gas plenum 442 (shown in FIG. 8) in the pedestal 114 as described below detail. During the post-ICE soak step, hydrogen from one of the gas sources 154 is introduced into the pedestal 114 via the valves 190 through the pocket gas plenum 466 (shown in FIG. 8) in the pedestal 114 as described below detail. The MFCs and the pressure controller 192 control the flow (e.g., flow rate and pressure) of the purge gas through the purge gas plenum 442 and control the flow (e.g., flow rate and pressure) of hydrogen through the pocket gas plenum 466, respectively.

[0060] A vacuum pump 172 is connected to the pedestal 114 via a valve 170. To clamp the substrate 124 to the pedestal 114, the vacuum pump 172 creates vacuum on the top surface of the pedestal 114 by evacuating gases in the station 112 via a vacuum clamping plenum 472 (shown in FIG. 8) and vacuum clamping grooves (shown in FIGS. 3 and 8).

[0061] The substrate processing system 110 comprises a controller 180. The controller 180 controls the valves 156, 190, and 170; the MFCs 158, the MFCs and pressure controller 192; the heaters in the pedestal 114 and the showerhead 116; the RF power supply 160; and the vacuum pump 172. The controller 180 also controls the index spindle that operates the transfer robot 20 and controls the height of the carrier ring 125 during the post-ICE soak step as described below. The controller 180 monitors the temperatures of the pedestal 114 and the showerhead 116 using the temperature sensors 164 and 168 in the pedestal 114 and the showerhead 116, respectively. The controller 180 controls the temperatures of the pedestal 114 and the showerhead 116 by controlling the heaters in the pedestal 114 and the showerhead 116, respectively.

[0062] Additionally, while not shown, the substrate processing system 100 may also comprise a cooling system that supplies a coolant to cooling channels in the pedestal 114 and the showerhead 116. The controller 180 controls the supply of the coolant to the cooling channels in the pedestal 114 and the showerhead 116 to control the temperatures of the pedestal 114 and the showerhead 116, respectively.EXAMPLE OF PEDESTAL

[0063] FIGS. 3 and 4 show the pedestal 114 in further detail. FIG. 3 shows a perspective view of the pedestal 114. FIG. 4 shows a top view of the pedestal 114. FIG. 8 shows a cross-sectional view of the pedestal 114. In the following description of theAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA views shown in FIGS. 3 and 4, elements such as the carrier ring 125 and the substrate 124 are referenced but are not shown.

[0064] In FIGS. 3 and 4, the pedestal 114 comprises the base portion 118 and the stem portion 120, which are already described above with reference to FIG. 2. The base portion 118 comprises a plurality of pockets 200-1 , 200-2, 200-3 (individually called the pocket 200 and collectively called the pockets 200). The pockets 200 are formed along an outer diameter (OD) (e.g., along an outer upper edge or periphery) of the base portion 118 of the pedestal 114. The pockets 200 are formed about 120 degrees apart from each other. The pockets 200 protrude or extend radially outwards from the OD (e.g., from the outer upper edge or periphery) of the of the base portion 118 of the pedestal 114.

[0065] Each pocket 200 comprises a slot 202 that extends radially into the outer periphery of the base portion 118 of the pedestal 114. The slots are shown at 202-1 , 202-2, 202-3 (individually called the slot 202 and collectively called the slots 202). The top ends of the pockets 200 are flush or level with (i.e., lie in the same plane as) the top surface of the base portion 118 of the pedestal 114.

[0066] A plurality support assemblies (not shown) are attached to the bottom of the carrier ring 125. The support assemblies are also disposed on the bottom side of the carrier ring 125 about 120 degrees apart from each other. When the carrier ring 125 comprising the support assemblies is placed on the top surface of the base portion 118 of the pedestal 114, the support assemblies align with and lie in respective slots 202 in the pockets 200. Thus, the pockets 200 support the carrier ring 125 and the support assemblies attached to the bottom of the carrier ring 125 when the carrier ring 125 with the substrate 124 is transported to and from the pedestal 114.

[0067] Each support assembly of the carrier ring 125 comprises a finger-like protrusion 127 (shown in FIG. 2) that supports the substrate 124 when the substrate 124 is transported to and from the pedestal 114 with the carrier ring 125. The protrusions (called fingers) 127 extend radially inwards from the carrier ring 125 and lie in the respective slots 202 in the pockets 200. After the transfer robot 20 moves the carrier ring 125 comprising the support assemblies holding the substrate 124 into the station 112, the carrier ring 125 with the support assemblies is lowered by the index spindle (shown at 20 in FIG. 1 ). The support assemblies lie in the pockets 200, and the fingers 127 lie in the slots 202 in the pockets 200. The substrate 124 lies on (and is clampedAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA to) the top surface of the base portion 118 of the pedestal 114. The support assemblies lie in a plane lower than the top surface of the base portion 118 of the pedestal 114. The fingers 127 do not contact the substrate 124. After processing the substrate 124 in the station 112, the carrier ring 125 with the support assemblies is lifted up by the index spindle, and the substrate 124 is picked by the fingers 127. The transfer robot 20 removes the carrier ring 125 with the substrate 124 resting on the fingers 127 of the support assemblies of the carrier ring 125 from the station 112 and transfers the carrier ring 125 and the substrate 124 to another station 112 of the tool 10.

[0068] For vacuum clamping, the top surface of the pedestal 114 also comprises a plurality of grooves 210 to clamp the substrate 124 to the top surface of the pedestal 114. The grooves 210 comprise radial grooves, concentric (i.e., annular or circular) grooves, and so on. The grooves 210 are collectively called vacuum clamping grooves or simply the clamping groove 210. The grooves 210 are connected to each other. Some of the radial clamping grooves 210 intersect the concentric clamping grooves 210 while some of the radial clamping grooves 210 interconnect the concentric clamping grooves 210. The radial clamping grooves 210 that intersect the concentric clamping grooves 210 are longer than the radial clamping grooves 210 that interconnect the concentric clamping grooves 210. Thus, all of the radial and concentric clamping grooves 210 are interconnected. The clamping grooves 210 are distributed within a circular region of the base portion 118 of the pedestal 114. The diameter of the circular region is less than the diameter of the substrate 124. The clamping grooves 210 near the center of the base portion 118 of the pedestal 114 are in fluid communication with a conduit (shown at 476 in FIG. 8) disposed in the stem portion 120 of the pedestal 114. The conduit 476 is in fluid communication with the vacuum pump 172 shown in FIG. 2.

[0069] The base portion 118 of the pedestal 114 also comprises a circular (annular) groove 240 that lies outside the circular region comprising the vacuum clamping grooves 210. An inner diameter (ID) of the groove 240 and a diameter of the substrate 124 are greater than the diameter of the circular region comprising the clamping grooves 210. The ID of the groove 240 is also greater than the diameter of the substrate 124. The groove 240 and the diameter of the substrate 124 intersect the radially inner ends of the slots 202 in the pockets 200. A purge gas such as argon is supplied through the groove 240 during processing of the substrate 124 using the DID steps. The purge gas is not supplied through the groove 240 during the post-ICE soak step. Instead, while not visible in FIGS. 3 and 4, during the post-ICE soak step,Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA hydrogen is supplied only to the pockets 200 through the separate pocket gas plenum 466 and angular holes 462 that open into the pockets 200 as shown and described below in detail with reference to FIG. 8.BACKSIDE DEPOSITION IN POCKET AREAS

[0070] FIG. 5 shows backside of the substrate 124 when the post-ICE soak step of the present disclosure is not used in the DID steps to fill high-aspect ratio features on the substrate 124. Areas 123-1 , 123-2, 123-3 of the backside of the substrate 124 lie above portions of the pockets 200-1 , 200-2, 200-3 of the pedestal 114, respectively. Specifically, the areas 123-1 , 123-2, 123-3 of the backside of the substrate 124 lie above portions of the slots 202-1 , 202-2, 202-3 in the pockets, respectively. The areas 123-1 , 123-2, 123-3 of the backside of the substrate 124 are collectively called pocket areas 123. The pocket areas 123 may also be called overhang areas 123 since an outer edge of the substrate 124 partially overhangs above portions of the slots 202 in the pockets 200. When the DID steps are performed without the post-ICE soak step of the present disclosure, tungsten nitride gets deposited on the pocket areas 123 during the ICE step as described above. The deposition of tungsten nitride on these pocket areas adversely impacts filling of high-aspect ratio features on the top surface of the substrate 124 and the within wafer non-uniformity (WiW NU) as described above.POST-ICE SOAK STEP

[0071] FIGS. 6 and 7 show different ways of supplying hydrogen from the pedestal 114 to the pocket areas 123 on the backside of the substrate 124 to remove (reduce as in the chemical reaction called reduction) the tungsten nitride deposited on the pocket areas 123 of the substrate 124. In FIGS. 6 and 7, the flow of hydrogen supplied through the pocket gas plenum 466 and the angular holes 462 in the pedestal 114 (shown in FIG. 8) to the pocket areas 123 on the backside of the substrate 124 is shown by arrows. A detailed structure of the pedestal 114 showing the pocket gas plenum 466 and the angular holes 462 used to supply hydrogen to the pocket areas 123 is shown and described below with reference to FIG. 8.

[0072] In FIG. 6, the carrier ring 125 is located closer to the pedestal 114 than in FIG. 7. In FIG. 6, hydrogen supplied to the pocket areas 123 reduces (as in a chemical reaction called reduction) tungsten nitride deposited on the pocket areas 123 of the substrate 124 but also flows partially over and across the top surface of the substrate 124 as shown by the arrows. Hydrogen flowing over the top surface of the substrateAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA can also reduce tungsten nitride deposited in the features on the top surface of the substrate 124, which is undesirable. Therefore, the height of the carrier ring 125 relative to the pedestal 114 needs to be adjusted so that hydrogen will not flow over and across the top surface of the substrate 124.

[0073] In FIG. 7, the height of the carrier ring 125 relative to the pedestal 114 is selected so that hydrogen does not flow over and across the top surface of the substrate 124 and prevents reduction of tungsten nitride deposited in the features on the top surface of the substrate 124. The MFC and pressure controller 192 (shown in FIG. 2) can also adjust the flow rate and pressure at which hydrogen is supplied to the pocket areas 123 so that hydrogen does not flow over and across the top surface of the substrate 124. Instead, after chemically reducing tungsten nitride deposited on the pocket areas 123 of the substrate 124, hydrogen flows though the gap between the substrate 124 and the carrier ring 125, which is created by adjusting the height of the carrier ring 125 relative to the pedestal 114. Hydrogen flows through the gap upwards into the processing volume of the station 112. Residual hydrogen (i.e., hydrogen remaining after the chemical reduction of tungsten nitride), along with reactants (e.g., NH3) formed during the chemical reduction, is pumped out from the processing volume of the station 112 by the vacuum pump 172.

[0074] Thus, adjusting the height of the carrier ring 125 relative to the pedestal 114 prevents hydrogen from flowing over the top surface of the substrate 124 and chemically reducing tungsten nitride deposited in the features on the top surface of the substrate 124. At the same time, adjusting the height of the carrier ring 125 relative to the pedestal 114 does not affect the chemical reduction of tungsten nitride deposited on the pocket areas 123 of the substrate 124. The controller 180 (shown in FIG. 2) controls the index spindle (shown in FIG. 1 ) to adjust the height of the carrier ring 125 as shown in FIG. 7. The controller 180 also controls the MFC and the pressure controller 192 (shown in FIG. 2) to control the flow rate and pressure of hydrogen and the duration for which hydrogen flows during the post-ICE soak step (i.e., the duration of the post-ICE soak step.CROSS-SECTION OF PEDESTAL

[0075] FIG. 8 shows a cross-sectional view of the pedestal 114. The pedestal 114 is now described in detail. The pedestal 114 is made of a metallic material (e.g., aluminum or an alloy). In some examples, the pedestal 1 14 can be made of otherAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA materials such as a ceramic material. The pedestal 114 comprises the base portion 118 and the stem portion 120 as described above. The base portion 118 is generally cylindrical and extends radially along the x-axis. The stem portion 120 is also generally cylindrical and has a smaller diameter than the base portion 118. The stem portion 118 is coupled to a bottom of the stem portion 120 near the center of the base portion 118. The stem portion 120 extends along the z-axis. The stem portion 120 is hollow and confines multiple conduits as described below.

[0076] A plurality of gas conduits generally shown at 406 are disposed through the stem portion 120 and are connected to various plenums formed in the base portion 118 by different plates of the base portion 118 as described below. The conduits 406 supply gases to the plenums as described below. Additionally, as described below, additional conduits for supplying power to the heater 162 disposed in the base portion 118 and for sensing a temperature of the base portion 118 using the temperature sensor 164 in the base portion 118 are also disposed through the stem portion 120.

[0077] The base portion 118 comprises four plates that are joined (e.g., brazed) together: a first plate 410, a second plate 412, a third plate 414, and a fourth plate 416. The plates 410, 412, 414, 416 are generally cylindrical. The stem portion 120 is coupled to the first plate 410. The heater 162 is disposed in the second plate 412. The various plenums described below are defined by the second, third, and fourth plates 412, 414, 416. The fourth plate 416 is also called the top plate 416 of the pedestal 114 on which the substrate 124 (see FIG. 2) is placed during processing. The plates also form the pockets 200 of the pedestal 114 as described below.

[0078] The fourth plate 416 comprises various grooves shown in FIGS. 3 and 4. For example, the top plate 416 comprises the circular (annular) groove 240 and the clamping grooves generally shown at 210 (also see FIGS. 3 and 4). The clamping grooves 210 comprise all of the grooves shown within (i.e., radially inside) the circular groove 240 as shown in FIGS. 3 and 4. The circular (annular) groove 240 is radially the outermost groove on the top surface of the fourth plate 416. An inner diameter (ID) of the circular groove 240 is greater than a diameter of the substrate 124 (represented by the dotted circle). An outer diameter (OD) of the circular groove 240 is less than a diameter of the fourth plate 416. The grooves 210 and 240 are connected to respective disjoint plenums in the base portion 118 of the pedestal 114 and to respective conduits described below.Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA

[0079] The pedestal 114 comprises the pockets 200. As described above, the pockets 200 support the carrier ring 125 (see FIG. 2) when the substrate 124 is transported to and from the pedestal 114. The pockets 200 are formed along an outer diameter (OD) (e.g., along an outer upper edge or periphery) of the base portion 118 of the pedestal 114. The plurality of the plates 412-416 form portions of the pockets 200. The pockets 200 are formed when the plurality of plates 412-416 are bonded (e.g., brazed, welding, soldering, etc.) together. Thus, the pockets 200 are homogeneous with (i.e., integral parts of) the plurality of plates 412-416 and the base portion 118 of the pedestal 114. The pockets 200 are formed about 120 degrees apart from each other. The pockets 200 protrude out of the OD of the of the base portion 118 of the pedestal 114 and extend along the x and y axes. The top ends of the pockets 200 are flush or level with (i.e., lie in the same plane as) the top surface of the fourth plate 416.

[0080] Each of the pockets 200 comprises a slot 202 that extends radially into an outer periphery of the base portion 118 of the pedestal 114. The circular groove 240 intersects slots 202 in the pockets 200. The circular groove 240 comprises a plurality of through holes 423. At least one through hole 423 in the circular groove 240 lies in each of the slots 202. As described above, the carrier ring 125 and the support assemblies is disposed in the slot 202 in the pocket 200. Each support assembly of the carrier ring 125 comprises the finger-like protrusion 127 (shown in FIG. 2) to support the substrate 124. As described below, an inert purge gas (e.g., Ar) is supplied through the circular groove 240 and the through holes 423 in the slots 202 of the pockets 200 during the DID steps but not during the post-ICE soak step. The fourth plate 416 comprises an additional set of the angular holes 462 that open into the pockets 200. During the post- ICE soak step, the angular holes 462 are supplied with hydrogen by a separate plenum formed in the base portion 118 of the pedestal 114 as described below.

[0081] The top surface of the second plate 412, the bottom surface of the third plate 414, and the through holes 423 in the third and fourth plates 414, 416 define a purge gas plenum 442 (also called an edge gas plenum). The second plate 412 comprises an annular groove 421 and a plurality of radial grooves 425 in the upper portion of the second plate 412. The radial grooves 425 extend from a hole 490 in the lower portion of the second plate 412 to the annular groove 421 . The hole 490, the radial grooves 425, and the annular groove 421 are in fluid communication with each other. The bottom surface of the third plate 414 is flat. Thus, the bottom surface of the third plate 414, theAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA annular groove 421 , the radial grooves 425, and the hole 490 define the purge gas plenum 442.

[0082] The through holes 423 in the circular groove 240 extend through the third and fourth plates 414, 416 and open in the purge gas groove 240 on the top surface of the fourth plate 416. The circular groove 240 (also called a purge gas groove or an edge gas groove), the through holes 423 in the third and fourth plates 414, 416, and the purge gas plenum 442 are in fluid communication with each other and can be collectively called the purge gas plenum 442. An inert purge gas (also called an edge gas) such as argon (Ar) is supplied through the purge gas plenum 442 during the DID steps. The inert purge gas is not supplied through the purge gas plenum 442 during the post-ICE soak step.

[0083] A conduit 444 passes through the first plate 410 and partially through the second plate 412 and is connected to the hole 490 in the second plate 412. Thus, the conduit 444 is connected to the purge gas plenum 442. The purge gas groove 240, the through holes 423, the purge gas plenum 442, and the conduit 444 are in fluid communication with each other. The purge gas groove 240, the through holes 423, the purge gas plenum 442, and the conduit 444 may be called the first groove 240, the first set of holes 423, the first plenum 442, and the first conduit 444, respectively.

[0084] A top surface of the third plate 414 and a bottom surface of the fourth plate 416 define the pocket gas plenum 466 as follows. The third plate 414 also comprises an annular groove 431 and a plurality of radial grooves 433 in the upper portion of the third plate 414. The radial grooves 433 extend from a hole 492 in the lower portion of the third plate 414 to the annular groove 431. The hole 492, the radial grooves 433, and the annular groove 431 are in fluid communication with each other. The bottom surface of the fourth plate 416 is flat. Thus, the bottom surface of the fourth plate 416, the annular groove 431 , the radial grooves 433, and the hole 492 define the pocket gas plenum 466.

[0085] The pocket gas plenum 466 is in fluid communication with the angular holes 462 in the fourth plate 416. The angular holes 462 open into the slots 202 in the pockets 200. Each pocket 200 comprises at least one angular hole 462. In some examples, the angular holes 462 are drilled through the fourth plate 416 and extend angularly upwards and radially outwards through the fourth plate 416 at an acute angle relative to the z-axis and open into the pockets 200. Hydrogen is supplied through theAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA pocket gas plenum 466 and the angular holes 462 into the slots 202 in the pockets 200. The pocket gas plenum 466 and the angular holes 462 can be collectively called the pocket gas plenum 466.

[0086] A conduit 468 passes through the first and second 410, 412, and partially through the third plate 414 and is connected to the pocket gas plenum 466. The pocket gas plenum 466, the angular holes 462, and the conduit 468 are in fluid communication with each other. The pocket gas plenum 466, the angular holes 462, and the conduit 168 can be called the second plenum 466, the second set of holes 462, and the second conduit 168, respectively. The first groove 240, the first set of holes 423, the first plenum 442, and the first conduit 444 that supply the inert purge gas (e.g., Ar) are separate, distinct, and disjoint from (i.e., are not in fluid communication with) the second plenum 466, the second set of holes 462, and the second conduit 168 that supply hydrogen to the slots 202 in the pockets 200.

[0087] For vacuum clamping the substrate 124 to the pedestal 114, the third plate 414 comprises a though hole 471 , and the fourth plate 416 comprises one or more through holes 470. The clamping grooves 210 on the top surface of the fourth plate 416, the through holes 470 in the fourth plate 416, and the through hole 472 in the third plate 414 define a vacuum clamping plenum. The clamping grooves 210, the through holes 470, and the through hole 472 are collectively called the vacuum clamping plenum generally identified at 472. A conduit 476 passes through the first and second 410, 412, and is connected to the through hole 472. The through holes 470, the through hole 472, the clamping grooves 210, and the conduit 476 are in fluid communication with each other. Thus, the conduit 476 is connected to the vacuum clamping plenum 472. The vacuum clamping plenum 472 and the conduit 476 may be called the third plenum 472 and the third conduit 476, respectively.

[0088] The through holes 470, the through hole 472, the clamping grooves 210, and the conduit 476 are disjoint from (i.e., are not in fluid communication with) the angular holes 462, the pocket gas plenum 466, and the conduit 468. The through holes 470, the through hole 472, the clamping grooves 210, and the conduit 476 are also disjoint from (i.e., are not in fluid communication with) the purge gas groove 240, the through holes 423, the purge gas plenum 442, and the conduit 444.

[0089] Due to the disjoint structures of the first, second, and third plenums 442, 466, 472 as described above, the gases flowing through each of the first, second, and thirdAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA plenums 442, 466, 472 do not mix with each other. The first gas flowing through the first plenum 442 does not mix the gases flowing through each of the second and third plenums 466, 472. The second gas flowing through the second plenum 466 does not mix the gases flowing through each of the first and third plenums 442, 472. The third gas flowing through the third plenum 472 also does not mix the gases flowing through each of the first and second plenums 442, 466.

[0090] Additionally, a pair of conduits 480, 482 pass through the stem portion 120 of the pedestal 114 and through the first plate 410 and comprise conductors connected to the heater 162. The controller 180 (see FIG. 2) controls power supplied to the heater 162 through the conductors in the conduits 480, 482. A conduit 484 passes through the stem portion 120 of the pedestal 114, through the first plate 410, and into the second plate 412. The conduit 484 comprises connection to the temperature sensor 164 (see FIG. 2), which is located at the end of the conduit 484 and is disposed to the second plate 412 to sense the temperature of the pedestal 114 (e.g., temperature of the base portion 118 of the pedestal 114). In some examples, the temperature sensor 164 may be disposed in the third plate 414, and the conduit 484 may pass through the second plate 412 and may contact the bottom surface of the third plate 414 or may be inserted into the bottom of the third plate 414 to connect to the temperature sensor 164.

[0091] The supply of various gases to the various plenums during substrate processing is now described. A first gas (e.g., an inert gas such as Ar), which is also called a purge gas or an edge gas, is supplied through the first plenum (i.e., the purge gas plenum) 442. The purge gas is supplied during the DID steps but is not supplied during the post-ICE soak step, which is performed between the ICE step and the CVD step. The purge gas improves edge uniformity along the edge (e.g., OD and bevel edges) of the substrate 124 during substrate processing.

[0092] A second gas (hydrogen) is supplied through the second plenum (i.e., the pocket gas plenum) 466 during the post-ICE soak step. As described above, hydrogen reduces (as in the chemical reaction called reduction) tungsten nitride from the pocket areas 123 (see FIG. 5) on the backside of the substrate 124 that is deposited in the ICE step. The second gas improves the tungsten fill performed subsequently in the CVD step and also improves the within wafer non-uniformity (WiW NU) of the full stack of layers deposited on the substrate using the DID steps.Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA

[0093] To process the substrate 124 (i.e., to fill the features on the substrate 124 with tungsten), the substrate 124 is arranged on the pedestal 114 in the station 112 (see FIG. 2). Before processing the substrate 124, the substrate 124 is clamped to the top surface of the fourth plate 416 of the pedestal 1 14. To clamp the substrate 124, the vacuum pump 172 (shown in FIG. 2) evacuates gases in the station 1 12 by removing gases from the station 1 12 though the third plenum (i.e., the vacuum clamping plenum 472 described above). Also, during the post-ICE soak step, the vacuum pump 172 evacuates hydrogen and reactants (e.g., NH3), which are formed during the reduction of the tungsten nitride from the pocket areas 123 (see FIG. 5) on the backside of the substrate 124 by hydrogen during the post-ICE soak step, from the station 112 though the third plenum (i.e., the vacuum clamping plenum 472 described above). The heater 162 heats the substrate 124 during the DID steps and the post-ICE soak step.METHOD COMPRISING POST-ICE SOAK STEP

[0094] FIG. 9 shows a method 500 of filling high-aspect ratio features on the substrate 124 using the DID steps and the additional post-ICE soak step according to the present disclosure. For example, the controller 180 performs the method 500 by controlling gas flows to the station 1 12 through the showerhead 1 16 and the pedestal 1 14 as described above and below.

[0095] At 502, the method 500 deposits a seed layer of tungsten (i.e., the nucleation step) using ALD while supplying a purge gas (e.g., Ar) to the backside of the substrate 124 from the pedestal 1 14. For example, the step 502 is performed a first station 1 12 where a mixture of tungsten hexafluoride (WFe) and diborane (B2H6) is supplied through the showerhead 1 16 to a heated substrate 1 14.

[0096] At 504, the method 500 deposits an ICE layer of tungsten nitride (i.e., the ICE step) while supplying the purge gas (e.g., Ar) to the backside of the substrate 124 from the pedestal 1 14. For example, the step 504 is performed a second station 112 where a mixture of tungsten hexafluoride (WFe) and ammonia (NH3) is supplied through the showerhead 1 16 to a heated substrate 114.

[0097] At 506, after the step 504, in the same second station 112 in which the step 504 is performed, the method 500 stops supplying gases through the showerhead 1 16 and stops supplying the purge gas (e.g., Ar) to the backside of the substrate 124 from the pedestal 114. The method 500 adjusts the height of the carrier ring 125 relative to the pedestal 1 14 at a selected height. For example, the method 500 empirically selectsAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA a gap between the carrier ring 125 and the top surface of the pedestal 114 (i.e., the height of the carrier ring 125 relative to the pedestal 114).

[0098] At 508, the method 500 supplies hydrogen only to the pocket areas 123 on the backside of the substrate 124 from the pedestal 114 to remove tungsten nitride from the pocket areas 123 on the backside of the substrate 124. The method 500 supplies hydrogen at a selected flow rate and for a selected time period (duration). For example, the method 500 selects the flow rate and the duration for supplying hydrogen based on a thickness of tungsten nitride deposited in the pocket areas 123 on the backside of the substrate 124. For example, the method 500 may determine the thickness based on one or more factors. For example, the factors may comprise the duration of the nucleation step, the thickness of the seed layer (which can be predetermined or determined based on the duration of the nucleation step), and specifications (e.g., dimensions) of the features being filled. For example, the method 500 may also determine the flow rate and duration of supplying hydrogen based on the surface area of the pocket areas 123 on the backside of the substrate 124. For example, the method 500 may determine the surface area of the pocket areas 123 based on the geometry of the pocket areas 200, the slots 202, and the diameter of the substrate 124.

[0099] At 510, the method 500 fills the features on the substrate 124 by depositing tungsten into the features using CVD while supplying a purge gas (e.g., Ar) to the backside of the substrate 124 from the pedestal 114. For example, the step 508 is performed a third station 112 where a mixture of tungsten hexafluoride (WFe) and hydrogen is supplied through the showerhead 116 to a heated substrate 114. The method 500 ends.

[0100] The foregoing description is merely illustrative in nature and is not intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims.

[0101] It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the present disclosure. Further, although each of the examples is described above as having certain features, any one or more of those features described with respect to any one ofAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA the examples of the disclosure can be implemented in and / or combined with features of any of the other examples, even if that combination is not explicitly described. In other words, the described examples are not mutually exclusive, and permutations of one or more examples with one another remain within the scope of this disclosure.

[0102] Spatial and functional relationships between elements (for example, between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including “connected,” “engaged,” “coupled,” “adjacent,” “next to,” “on top of,” “above,” “below,” and “disposed.” Unless explicitly described as being “direct,” when a relationship between first and second elements is described in the above disclosure, that relationship can be a direct relationship where no other intervening elements are present between the first and second elements, but can also be an indirect relationship where one or more intervening elements are present (either spatially or functionally) between the first and second elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”

[0103] In some implementations, a controller is part of a system, which may be part of the above-described examples. Such systems can comprise semiconductor processing equipment, including a processing tool or tools, chamber or chambers, a platform or platforms for processing, and / or specific processing components (a substrate support, a gas flow system, etc.). These systems may be integrated with electronics for controlling their operation before, during, and after processing of a semiconductor wafer or substrate.

[0104] The electronics may be referred to as the “controller,” which may control various components or subparts of the system or systems. The controller, depending on the processing requirements and / or the type of system, may be programmed to control any of the processes disclosed herein, including the delivery of processing gases, temperature settings (e.g., heating and / or cooling), pressure settings, vacuum settings, power settings, radio frequency (RF) generator settings, RF matching circuit settings, frequency settings, flow rate settings, fluid delivery settings, positional and operation settings, wafer transfers into and out of a tool and other transfer tools and / or load locks connected to or interfaced with a specific system.Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA

[0105] Broadly speaking, the controller may be defined as electronics having various integrated circuits, logic, non-transitory memory, and / or software that receive instructions, issue instructions, control operation, enable cleaning operations, enable endpoint measurements, and the like. The integrated circuits may include chips in the form of firmware that store program instructions, digital signal processors (DSPs), chips defined as application specific integrated circuits (ASICs), and / or one or more microprocessors, or microcontrollers that execute program instructions (e.g., software).

[0106] Program instructions may be instructions communicated to the controller in the form of various individual settings (or program files), defining operational parameters for carrying out a particular process on or for a semiconductor wafer or to a system. The operational parameters may, in some examples, be part of a recipe defined by process engineers to accomplish one or more processing steps during the fabrication of one or more layers, materials, metals, oxides, silicon, silicon dioxide, surfaces, circuits, and / or dies of a wafer.

[0107] The controller, in some implementations, may be a part of or coupled to a computer that is integrated with the system, coupled to the system, otherwise networked to the system, or a combination thereof. For example, the controller may be in the “cloud” or all or a part of a fab host computer system, which can allow for remote access of the wafer processing. The computer may enable remote access to the system to monitor current progress of fabrication operations, examine a history of past fabrication operations, examine trends or performance metrics from a plurality of fabrication operations, to change parameters of current processing, to set processing steps to follow a current processing, or to start a new process.

[0108] In some examples, a remote computer (e.g., a server) can provide process recipes to a system over a network, which may include a local network or the Internet. The remote computer may include a user interface that enables entry or programming of parameters and / or settings, which are then communicated to the system from the remote computer. In some examples, the controller receives instructions in the form of data, which specify parameters for each of the processing steps to be performed during one or more operations. It should be understood that the parameters may be specific to the type of process to be performed and the type of tool that the controller is configured to interface with or control.Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA

[0109] Thus, as described above, the controller may be distributed, such as by comprising one or more discrete controllers that are networked together and working towards a common purpose, such as the processes and controls described herein. An example of a distributed controller for such purposes would be one or more integrated circuits on a chamber in communication with one or more integrated circuits located remotely (such as at the platform level or as part of a remote computer) that combine to control a process on the chamber.

[0110] Without limitation, example systems may include a plasma etch chamber or module, a deposition chamber or module, a spin-rinse chamber or module, a metal plating chamber or module, a clean chamber or module, a bevel edge etch chamber or module, a physical vapor deposition (PVD) chamber or module, a chemical vapor deposition (CVD) chamber or module, an atomic layer deposition (ALD) chamber or module, an atomic layer etch (ALE) chamber or module, an ion implantation chamber or module, a track chamber or module, and any other semiconductor processing systems that may be associated or used in the fabrication and / or manufacturing of semiconductor wafers.

[0111] As noted above, depending on the process step or steps to be performed by the tool, the controller might communicate with one or more of other tool circuits or modules, other tool components, cluster tools, other tool interfaces, adjacent tools, neighboring tools, tools located throughout a factory, a main computer, another controller, or tools used in material transport that bring containers of wafers to and from tool locations and / or load ports in a semiconductor manufacturing factory.

Claims

Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POACLAIMSWhat is claimed is:1 . A method comprising: depositing an inhibitor controlled enhanced (ICE) layer on a top surface of a substrate arranged on a pedestal, the deposition of the ICE layer on the top surface of the substrate depositing a film on areas on a bottom surface of the substrate; and supplying, after depositing the ICE layer, a gas through the pedestal to the areas on the bottom surface of the substrate to remove the film deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.

2. The method of claim 1 further comprising, after depositing the ICE layer and before supplying the gas: adjusting a height of a carrier ring used to transport the substrate to form a gap between the substrate and the carrier ring through which the gas flows to the areas on the bottom surface of the substrate without flowing over the top surface of the substrate; and selecting a duration and at least one of a flow rate and a pressure at which the gas is supplied to the areas on the bottom surface of the substrate to remove the film deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.

3. The method of claim 1 wherein: depositing the ICE layer comprises supplying a mixture of ammonia and tungsten hexafluoride from a showerhead to the substrate arranged on the pedestal, the mixture forming the film comprising tungsten nitride on the areas on the bottom surface of the substrate that are exposed to the mixture; and supplying the gas comprises supplying hydrogen through the pedestal to the areas on the bottom surface of the substrate to reduce the film comprising tungsten nitride deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA4. The method of claim 1 further comprising: depositing, before depositing the ICE layer, a seed layer of tungsten in a feature on the top surface of the substrate; depositing the ICE layer in the feature after depositing the seed layer, the deposition of the ICE layer depositing the film of tungsten nitride on the areas on the bottom surface of the substrate; reducing, after depositing the ICE layer, the film of tungsten nitride by supplying the gas, the gas being hydrogen; and depositing tungsten in the feature after the reduction of the film of tungsten nitride.

5. The method of claim 4 further comprising: depositing the seed layer using atomic layer deposition; and depositing tungsten in the feature using chemical vapor disposition.

6. The method of claim 4 further comprising: depositing the seed layer in a first station by supplying a mixture of tungsten hexafluoride and diborane to the first station; depositing the ICE layer in a second station by supplying a mixture of ammonia and tungsten hexafluoride to the second station; reducing the film of tungsten nitride by supplying the gas to the second station; and depositing tungsten in the feature in a third station by supplying a mixture of tungsten hexafluoride and hydrogen to the third station.

7. A method of filling a feature on a substrate with tungsten comprising: depositing, in a first station, a seed layer of tungsten in the feature using atomic layer deposition by supplying a mixture of tungsten hexafluoride and diborane through a first showerhead in the first station; depositing, in a second station, after depositing the seed layer, an inhibitor controlled enhanced (ICE) layer in the feature by supplying a mixture of ammonia and tungsten hexafluoride through a second showerhead in the second station, the deposition of the ICE layer depositing a film of tungsten nitride on areas on a bottom surface of the substrate;Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA reducing, in the second station, after depositing the ICE layer, the film of tungsten nitride by supplying hydrogen to the second station; and depositing, in a third station, after the reducing of the film of tungsten nitride, tungsten in the feature using chemical vapor deposition by supplying a mixture of tungsten hexafluoride and hydrogen through a third showerhead in the third station.

8. The method of claim 7 further comprising: supplying an inert gas through pedestals in the first, second, and third stations during the atomic layer deposition, deposition of the ICE layer, and the chemical vapor deposition; and supplying only hydrogen through the pedestal in the second station during the reduction of the film of tungsten nitride.

9. The method of claim 7 further comprising, after depositing the ICE layer and before the reduction of the film of tungsten nitride: adjusting, in the second station, a height of a carrier ring used to transport the substrate between the first, second, and third stations to form a gap between the substrate and the carrier ring through which hydrogen flows without flowing over the feature; and selecting a duration and at least one of a flow rate and a pressure at which hydrogen is supplied to remove the film of tungsten nitride from the areas on the bottom surface of the substrate.

10. A system comprising: a pedestal comprising: a base portion; a plurality of pockets located around a periphery of the base portion, the pockets comprising slots configured to receive a carrier ring carrying a substrate, the substrate partially extending over the slots in the pockets; and a plenum defined in the base portion, the plenum comprising angular holes opening into the slots in the pockets; and a controller configured to: deposit an inhibitor controlled enhanced (ICE) layer on a top surface of the substrate; andAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA supply, after depositing the ICE layer, a gas through the angular holes to areas on a bottom surface of the substrate that lie above the slots.11 . The system of claim 10 wherein the controller is configured to: raise the carrier ring above the base portion to a height selected to form a gap between the substrate and the carrier ring through which the gas flows to the areas on the bottom surface of the substrate without flowing over the top surface of the substrate; and select a duration and at least one of a flow rate and a pressure for supplying the gas to the areas on the bottom surface of the substrate to remove a film deposited on the areas on the bottom surface of the substrate during the deposition of the ICE layer on the top surface of the substrate.

12. The system of claim 10 further comprising: a showerhead configured to supply a mixture of ammonia and tungsten hexafluoride to deposit the ICE layer on the top surface of the substrate, the deposition of the ICE layer on the top surface of the substrate depositing a film of tungsten nitride on the areas on the bottom surface of the substrate; and wherein the controller is configured to supply hydrogen as the gas to the areas on the bottom surface of the substrate to reduce the film of tungsten nitride deposited on the areas on the bottom surface of the substrate.

13. A system comprising: a first station to perform a first process on a substrate, the first station comprising a first showerhead and a first pedestal; a second station to perform a second process on the substrate, the second station comprising a second showerhead and a second pedestal; a third station to perform a third process on the substrate, the third station comprising a third showerhead and a third pedestal; wherein each of the first, second, and third pedestals comprises a base portion comprising: a plurality of pockets located around a periphery of the base portion, the pockets comprising slots configured to receive a carrier ring carrying the substrate, the substrate partially extending over the slots in the pockets; andAttorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA a pocket gas plenum defined in the base portion, the pocket gas plenum comprising angular holes opening into the slots in the pockets; and a controller configured to: deposit, in the first station, a seed layer of tungsten on a top surface of the substrate using the first process by supplying a mixture of tungsten hexafluoride and diborane through the first showerhead; deposit, in the second station, after depositing the seed layer, an inhibitor controlled enhanced (ICE) layer on the top surface of the substrate using the second process by supplying a mixture of ammonia and tungsten hexafluoride through the second showerhead, the deposition of the ICE layer depositing tungsten nitride on areas on a bottom surface of the substrate that lie above the slots in the pockets; reduce, in the second station, after depositing the ICE layer, the tungsten nitride from the areas on the bottom surface of the substrate by supplying hydrogen through the pocket gas plenum and the angular holes in the second pedestal to the slots in the pockets; and deposit, in the third station, after reducing the tungsten nitride from the areas on the bottom surface of the substrate, tungsten on the top surface of the substrate using the third process by supplying a mixture of tungsten hexafluoride and hydrogen through the third showerhead.

14. The system of claim 13 wherein the controller is configured to: supply, during the first, second, and third processes, an inert gas through a plenum in the first, second, and third pedestals that is different than the pocket gas plenum and the angular holes; and supply only hydrogen through the pocket gas plenum and the angular holes in the second pedestal to the slots in the pockets during the reduction of the tungsten nitride from the areas on the bottom surface of the substrate.Attorney Docket No. 11976-1 WOHDP Ref. No. 15545-001301 -WO-POA15. The system of claim 13 wherein the controller is configured to, after depositing the ICE layer and before the reduction of the tungsten nitride from the areas on the bottom surface of the substrate: adjust, in the second station, a height of the carrier ring used to transport the substrate between the first, second, and third stations to form a gap between the substrate and the carrier ring through which hydrogen flows to the slots in the pockets without flowing over the top surface of the substrate; and select a duration and at least one of a flow rate and a pressure at which hydrogen is supplied to the slots in the pockets to reduce the tungsten nitride from the areas on the bottom surface of the substrate.

16. The system of claim 13 wherein: the first process is atomic layer deposition; and the third process is chemical vapor deposition.

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