Precursor delivery system and method for cyclic deposition

Abstract

The disclosed technology is generally related to semiconductor manufacturing, and more specifically, to precursor delivery in cyclic deposition. In one embodiment, a method of depositing a thin film includes alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber. Exposing the substrate includes introducing one of the precursors into the thin film deposition chamber via two or more atomic layer deposition (ALD) valves, each of the two or more ALD valves being configured to supply that one of the precursors.

Description

Technical Field

[0001] The technology disclosed is broadly related to semiconductor manufacturing, and more specifically to precursor delivery in cyclic deposition. Prior Technology

[0002] As the lateral dimensions of semiconductor devices continue to shrink, the vertical dimensions of semiconductor devices are correspondingly shrinking, including the reduction in the thickness of functional thin films such as electrodes and dielectrics. Semiconductor manufacturing involves the deposition and patterning of various thin films throughout the manufacturing process. The thin films used in semiconductor manufacturing can be formed using various techniques, including wet deposition and dry deposition. Wet deposition methods include, for example, aerosol / spray deposition, sol-gel methods, and spin coating. Dry deposition methods include physical vapor deposition (PVD) based techniques and evaporation. Dry deposition methods also include precursor and / or chemical reaction based techniques, such as chemical vapor deposition (CVD) and cyclic deposition, such as atomic layer deposition (ALD). Summary of the Invention

[0003] In one embodiment, a thin film deposition system includes a thin film deposition chamber configured to deposit a thin film by alternately exposing a substrate to a plurality of precursors. The thin film deposition system is configured to introduce a first of the precursors into the thin film deposition chamber by independently actuating two or more first atomic layer deposition (ALD) valves, the two or more first ALD valves being connected in parallel to a common gas distribution plate to supply the first of the precursors into the thin film deposition chamber.

[0004] In another embodiment, a method for depositing a thin film includes alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber. Alternate exposure of the substrate includes introducing one of the precursors into the thin film deposition chamber via two or more atomic layer deposition (ALD) valves, each configured to supply one of the precursors, wherein two or more first ALD valves are connected in parallel to a common gas distribution plate to supply one of the precursors to the thin film deposition chamber.

[0005] In another embodiment, a method for depositing a thin film includes alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber in a plurality of cycles. Alternate exposure of the substrate includes introducing a first of the precursors into the thin film deposition chamber by independently actuating two or more first atomic layer deposition (ALD) valves, the two or more first ALD valves being connected in parallel to a common gas distribution plate to supply the first of the precursors into the thin film deposition chamber. Independently actuating two or more first ALD valves includes simultaneously opening two or more first ALD valves for at least a portion of the time during the introduction of the first of the precursors into the thin film deposition chamber during the same period in the cycle.

[0006] In another embodiment, a method for depositing a thin film includes alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber in a plurality of cycles. Alternately exposing the substrate includes introducing a first of the precursors into the thin film deposition chamber by independently actuating two or more first atomic layer deposition (ALD) valves, the two or more first ALD valves being connected in parallel to a common gas distribution plate to supply the first of the precursors to the thin film deposition chamber. Independently actuating the two or more first ALD valves includes actuating the first of the two or more first ALD valves during the first cycle and actuating the second of the two or more first ALD valves during the second cycle.

[0007] In another embodiment, a method for depositing a thin film includes alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber in a plurality of cycles. Alternately exposing the substrate includes introducing a first of the precursors into the thin film deposition chamber by independently actuating two or more first atomic layer deposition (ALD) valves, the two or more first ALD valves being connected in parallel to a common gas distribution plate to supply the first of the precursors to the thin film deposition chamber. Independently actuating two or more first ALD valves includes exposing the substrate to a plurality of pulses by alternately opening different of the two or more first ALD valves during the same period in a cycle. Simple Explanation of the Diagram

[0008] Figure 1 schematically illustrates a thin film deposition system according to an embodiment, including a thin film deposition chamber and a precursor delivery system configured to deliver the precursor using two or more atomic layer deposition (ALD) valves connected in parallel to a common gas distribution plate.

[0009] Figure 2 is a schematic diagram of a precursor delivery system configured according to an embodiment to deliver precursors using two or more atomic layer deposition (ALD) valves connected in parallel to a common gas distribution plate.

[0010] Figure 3A shows a perspective view of a multi-valve block assembly of a precursor delivery system configured to deliver precursors using two or more ALD valves connected in parallel to a common gas distribution plate, according to an embodiment.

[0011] Figure 3B shows a perspective view of one of the multiple valve blocks illustrated in Figure 3A according to an embodiment, wherein the multiple valve blocks are configured to be coupled in parallel to a plurality of ALD valves on a common gas distribution plate.

[0012] Figure 3C shows a perspective view of one of the ALD valves configured to be coupled to the multi-valve block illustrated in Figure 3B according to an embodiment.

[0013] Figure 3D is an example experimental diagram showing various signals associated with the actuation of an ALD valve, as illustrated in Figure 3C, according to the description of the embodiment.

[0014] Figure 4 shows a perspective view of the top exterior portion of a deposition chamber comprising multiple processing stations according to an embodiment, each configured to deliver precursors using two or more ALD valves connected in parallel to a common gas distribution plate.

[0015] Figure 5A illustrates an example precursor delivery sequence for thin film deposition according to some embodiments, including an exposure sequence of the precursor using two or more ALD valves connected in parallel to a common gas distribution plate in one cycle.

[0016] Figure 5B illustrates the precursor delivery conditions for a specific instance of cyclic deposition or ALD of TiN using TiCl4 and NH3, based on the delivery sequence illustrated in Figure 5A.

[0017] Figure 6 illustrates an example precursor delivery sequence for thin film deposition according to some embodiments, including an exposure sequence of the precursor using two or more ALD valves connected in parallel to a common gas distribution plate in two additional cycles.

[0018] Figure 7 illustrates an example precursor delivery sequence for thin film deposition according to some embodiments, including a precursor exposure sequence in which multiple pulses of precursor are delivered in one cycle using two or more ALD valves connected in parallel to a common gas distribution plate.

[0019] Figure 8 schematically illustrates a cross-sectional view of a liner with through-holes in a thin film layer deposited according to an embodiment. Implementation

[0020] [Incorporate by citing any priority claims] [ ] In accordance with 37 CFR § 1.57, any and all applications that identify foreign or domestic priority technologies in the application data form as applied in this application are incorporated herein by reference.

[0021] This application claims priority to U.S. Provisional Patent Application No. 63 / 142,238, filed January 27, 2021, entitled “PRECURSOR DELIVERY SYSTEM AND METHOD FOR CYCLIC DEPOSITION”, the contents of which are hereby expressly incorporated herein by reference in their entirety.

[0022] Cyclic deposition processes, such as atomic layer deposition (ALD), can provide relatively conformal films with high uniformity and thickness accuracy in relatively high aspect ratios (e.g., 2:1). While conformality and uniformity are generally worse compared to ALD, films deposited using continuous deposition processes, such as chemical vapor deposition (CVD), offer higher productivity and lower costs. ALD and CVD can be used to deposit a wide variety of films, including elemental metals, metal compounds (e.g., TiN, TaN, etc.), semiconductors (e.g., Si, III-V, etc.), dielectrics (e.g., SiO2, AlN, HfO2, ZrO2, etc.), rare earth oxides, conductive oxides (e.g., IrO2, etc.), ferroelectrics (e.g., PbTiO3, LaNiO3, etc.), superconductors (e.g., Yba2Cu3O7-x), and chalcogenides (e.g., GeSbTe), to name just a few.

[0023] Some cyclic deposition processes, such as atomic layer deposition (ALD), involve alternately exposing a substrate to a plurality of precursors to form a thin film. Different precursors can alternately saturate at least partially the surface of the substrate and react with each other, thereby forming a thin film layer by layer. Due to its layer-by-layer growth capability, ALD allows for precise control of thickness and composition, which in turn allows for precise control of various properties, such as conductivity, conformability, uniformity, barrier properties, and mechanical strength. Due to the nature of the deposition process in ALD, the precursor delivery system in ALD deposition systems faces unique challenges compared to precursor delivery systems in systems such as CVD deposition. For example, because the alternating exposure of the substrate to multiple precursors is repeated at a relatively high rate and / or at a relatively high frequency, the precursor delivery system or its components (such as precursor delivery valves) can directly or indirectly limit various aspects of the ALD deposition process, including its accuracy, yield, reliability, and operating costs.

[0024] As described herein, atomic layer deposition (ALD) valves refer to precursor delivery valves configured to introduce precursors into the ALD deposition chamber with high precision and speed (e.g., response time less than 30 ms) pulses, while also possessing high flow coefficients (e.g., Cv greater than 0.20). Because ALD deposition of thin films can involve several to thousands of alternating exposure cycles for different precursors, valve parameters (such as the flow rate, speed, and / or frequency of the ALD valve) can directly affect deposition yield and the efficiency of precursor utilization. Furthermore, wear of ALD valves between preventative maintenance services can limit the lifespan of some ALD systems. Delivery of some precursors at high temperatures can further limit the yield and lifespan of some ALD systems.

[0025] Therefore, a precursor delivery system is needed to improve throughput and speed, extend downtime, enhance temperature compatibility, and reduce maintenance. These capabilities can significantly reduce the total manufacturing and ownership costs of an ALD system. [Having two or more for delivering the same precursor] [ALD] [Valve precursor delivery system]

[0026] To address the aforementioned and other requirements, a thin film deposition system according to an embodiment includes a thin film deposition chamber configured to deposit a thin film by alternately exposing a substrate to a plurality of precursors. The thin film deposition chamber is configured to introduce one or more of the same precursors into the thin film deposition chamber using two or more atomic layer deposition (ALD) valves. This configuration via two or more ALD valves allows, for example, combined flow rates of one or more precursors that are significantly higher than those in conventional thin film deposition systems, thereby significantly reducing the duration of ALD cycles. For example, the duration of exposure to the precursor can be reduced proportionally to the number of ALD valves used to introduce the same precursor. For example, by using n ALD valves to introduce a given precursor, the exposure time can be reduced by approximately n times, while achieving a similar surface saturation that would be achieved using only one ALD valve.

[0027] In the following description, examples may be used to illustrate the use of specific precursors for specific films. For example, specific example precursors for depositing TiN and / or TiSiN, including TiCl4, NH3, and SiCl2H2, may be used to describe thin film deposition systems and methods for depositing thin films according to various embodiments. However, it will be understood that the embodiments are not limited thereto, and the present invention can be applied to any suitable combination of precursors for depositing any suitable thin film that can be formed using a cyclic deposition process such as ALD.

[0028] Figure 1 schematically illustrates a thin film deposition system configured to deliver gas using two or more atomic layer deposition (ALD) valves connected in parallel to a common gas distribution plate, according to an embodiment. The thin film deposition system 100 includes a thin film deposition chamber 102 and a precursor delivery system 106 configured to deliver a plurality of precursors into the deposition chamber 102. The illustrated deposition chamber 102 is configured to process a substrate 120 on a support 116, such as a pedestal, under process conditions. The deposition chamber 102 further includes a nozzle 108 configured to concentrate and discharge a plurality of precursors into the deposition chamber 102 via a gas distribution plate 112 (also referred to as a showerhead). The nozzle 108 can mix these gases before the gas distribution plate 112 diffuses gases, such as precursors and flushing gases, into the deposition chamber 102. The gas distribution plate 112 is configured to uniformly diffuse the precursors onto the substrate 120 on the pedestal 116, resulting in uniform deposition. The deposition chamber may be equipped with a pressure monitoring sensor (P) and / or a temperature monitoring sensor (T).

[0029] A precursor delivery system 106 is configured to deliver a plurality of precursors from precursor sources (120, 124) and one or more flushing gases (e.g., inert gases) from a flushing gas source (128) to a processing chamber. Each of the precursors and flushing gases is connected to the deposition chamber 102 via a separate gas delivery line. The gas delivery line further includes, in its path, a mass flow controller (MFC) 132 and separate precursor valves for introducing the respective precursors into the thin film deposition chamber. At least some of the valves may be atomic layer deposition (ALD) valves. The gas delivery line is connected to the deposition chamber 102 via a gas distribution plate 112.

[0030] Advantageously, according to various embodiments, the thin film deposition system 100 is configured such that at least one of the precursors can be introduced into the deposition chamber 102 by independently actuating two or more first atomic layer deposition (ALD) valves connected in parallel to a gas distribution plate 112 to supply one of the precursors to the thin film deposition chamber 102.

[0031] For illustrative purposes only, in the configuration illustrated in Figure 1, the plurality of precursors include a first precursor and a second precursor. The first precursor is stored in at least two first precursor sources 120-1, 120-2, and the second precursor is stored in at least two second precursor sources 124-1, 124-2. The purge gas may be stored in at least two purge gas sources 128-1, 128-2. The first precursor is configured to be delivered from the first precursor sources 120-1, 120-2 by independently actuating two separate first precursor atomic layer deposition (ALD) valves 140-1, 140-2 connected in parallel to a common gas distribution plate 112. Additionally, the second precursor is configured to be delivered from the second precursor sources 124-1 and 124-2 by independently actuating two separate second precursor atomic layer deposition (ALD) valves 144-1 and 144-2 connected in parallel to the common gas distribution plate 112. Furthermore, the purge gas is configured to be delivered from the purge gas sources 128-1 and 128-2 by independently actuating two separate purge gas atomic layer deposition (ALD) valves 148-1 and 148-2 connected in parallel to the common gas distribution plate 112. The ALD valves 140-1, 140-2, 144-1, 144-2, 148-1, and 148-2, and the respective delivery lines connected to the gas distribution plate 112, can be arranged to feed the respective gases to the nozzle 108 via a multi-valve block assembly 150 (FIG. 3A), which can be attached to the cover of the deposition chamber 102. In the described configuration, ALD valves 140-1, 140-2, 144-1, 144-2, 148-1 and 148-2 are the final valves before the respective gases are introduced into the deposition chamber 102.

[0032] As configured, the thin film deposition system 100 is configured to deliver precursors and / or flushing gases via two separate gas lines and using independently controlled ALD valves. Depending on the embodiment, the delivery pulses of the same precursors and / or flushing gases may overlap or not overlap in time.

[0033] By way of example only, the first and second precursors may respectively comprise TiCl4 and NH3, which are delivered from separate TiCl4 and NH3 sources to the deposition chamber 102 via separate precursor delivery lines to form, for example, TiN. The precursor delivery system may be additionally configured to deliver Ar as a flushing gas from an Ar source to the processing chamber via a flushing gas delivery line. The flushing gas may be delivered as a continuous flush (CP) gas that can be delivered via a precursor ALD valve, and / or as a rapid flush (RP) gas that can be delivered via a dedicated flushing gas ALD valve as shown in FIG. 1. The described precursor delivery system 106 may be configured to deliver Ar as an RP gas from flushing gas sources 128-1 and 128-2 to the processing chamber 102 via separate flushing gas delivery lines and flushing gas ALD valves 148-1 and 148-2.

[0034] According to various embodiments, the thin film deposition system 100 is configured for thermal ALD without the aid of plasma. While plasma-enhanced processes such as plasma-enhanced atomic layer deposition (PE-ALD) can effectively form conformal films on surfaces with relatively low aspect ratios, such processes may be ineffective when depositing films inside vias and cavities with relatively high aspect ratios. Without theoretical limitations, one possible reason is that the plasma may not be able to reach the deeper portions of high aspect ratio vias in some cases. In such cases, different portions of the via may be exposed to different amounts of plasma, resulting in undesirable structural effects caused by uneven deposition, such as a thicker film deposited closer to the via opening than the deeper portions (sometimes referred to as cusp or keyhole formation). For these reasons, thermal cycling vapor deposition, such as thermal ALD, may be more advantageous because such thermal processes do not depend on the ability of the plasma to reach portions of the deposited surface.

[0035] The described precursor delivery system 106 advantageously provides the ability to deliver a combined flow rate of a given precursor that is significantly higher than that of conventional thin film deposition systems by overlapping the activation of two or more ALD valves. This allows for a significant reduction in the duration of ALD cycles, a significant increase in the gas flow rate during ALD cycles, or both. For example, the duration of exposure to the precursor can be reduced proportionally to the number of ALD valves used to introduce the same precursor. Furthermore, by overlapping the activation of two or more ALD valves, the pressure inside the deposition chamber 102 during exposure can be advantageously increased to levels that cannot be achieved by a single ALD valve, such as >1 Torr.

[0036] Alternatively or concurrently, the described precursor delivery system 106 advantageously provides the capability of delivering a given precursor within the same sub-cycle using repeated pulses of a given precursor with minimal lag between pulses by rapidly alternating activation of two or more ALD valves.

[0037] Alternatively or concurrently, the described prior material delivery system 106 advantageously provides the capability by alternately activating two or more ALD valves to proportionally reduce wear on the ALD valves, thereby reducing the frequency of preventative maintenance that may be required to replace or repair the ALD valves.

[0038] Figure 2 is a schematic diagram of a precursor delivery system configured to deliver precursors using two or more atomic layer deposition (ALD) valves connected in parallel to a common gas distribution plate, according to an embodiment. According to the embodiment, precursor delivery system 206 is connected to deposition chamber 102 in a manner similar to that of precursor delivery system 106 illustrated in Figure 1. Deposition chamber 102 is configured to deliver three precursors via eight precursor ALD valves 140-1, 140-2, 144-1, 144-2, 220-1, 220-2, 220-3, and 220-4, and to deliver a purge gas, such as an inert gas, via two purge gas ALD valves 144-1 and 144-2, wherein each of the three precursors and the purge gas is delivered via two or more precursor ALD valves and purge gas ALD valves, respectively. Specifically, by way of example only, the illustrated precursor system 206 can be configured to deliver TiCl4 via two precursor ALD valves, SiCl2H2 via two precursor ALD valves, and NH3 via four precursor ALD valves. The precursor system 206 can also be configured to deliver an inert gas, such as Ar, via two or more purge ALD valves. Specifically, by way of example only, the illustrated precursor delivery system 206 is configured to form a thin film comprising any one of Ti, Si, and N (e.g., TiN, TiSi, or TiSiN). For example, system 206 is configured to deliver a first precursor (precursor 1), such as TiCl4, via two first precursor ALD valves 140-1 and 140-2, a second precursor (precursor 2), such as SiCl2H2, via two second precursor ALD valves 144-1 and 144-2, and a third precursor (precursor 3), such as NH3, via four third precursor ALD valves 220-1, 220-2, 220-3, and 220-4. Precursor delivery system 206 is also configured to deliver a flushing gas, such as N2 or Ar, via two flushing ALD valves 144-1 and 144-2. The ALD valves and the individual delivery lines connected thereto can be configured to feed the individual precursors and flushing gas into the deposition chamber 102 via a multi-valve assembly 250, which can be attached to the cover of the deposition chamber 102.

[0039] It should be understood that each of the described precursor ALD valves 140-1, 140-2, 144-1, 144-2, 220-1, 220-2, 220-3, and 220-4 is configured as a three-port valve, configured to simultaneously receive continuous flushing (CP) gas and precursor gas into their respective inlet ports and output both CP gas and precursor gas from their outlet ports into the deposition chamber 102. For example, the CP flushing gas, such as Ar or N2, enters through one inlet (first) port and exits through an outlet (second) port. The precursor gas enters through another inlet (third) port and also exits through an outlet (second) port. The inlet ports are small, precise orifices for delivering relatively small chemical volumes. This three-port configuration delivers a stable CP gas flow to the processing station while pulsating the precursor gas. CP gas is used to continuously flush individual delivery lines, promoting precursor movement into the deposition chamber and controlling the overall process pressure during deposition. On the other hand, each of the described flushing gas ALD valves 148-1 and 148-2 is configured as a dual-port valve, configured to receive rapid flushing (RP) gas into the inlet port and output RP gas into the deposition chamber 102. As configured, the flushing gas can be delivered as continuous flushing (CP) gas via each of the described precursor ALD valves 140-1, 140-2, 144-1, 144-2, 220-1, 220-2, 220-3, and 220-4, and / or as rapid flushing (RP) gas via each of the described flushing gas ALD valves 148-1 and 148-2. The inventors have discovered that the ability to allow CP flow through the precursor ALD valve can, in particular, achieve the shorter RP pulse duration required for flushing delivery lines, thereby improving overall speed and throughput.

[0040] Figure 3A shows a perspective view of a multi-valve block assembly configured according to an embodiment to deliver precursors using two or more atomic layer deposition (ALD) valves connected in parallel to a common gas distribution plate. The multi-valve block assembly 250, which corresponds schematically to the multi-valve block assembly 250 depicted in Figure 2, similarly corresponds to the multi-valve block assembly 150 schematically depicted in Figure 1. The multi-valve block assembly 250 is divided into two halves, each containing one of a first multi-valve block 304-1 and a second multi-valve block 304-2. A plurality of ALD valves are connected to each of the first multi-valve block 304-1 and the second multi-valve block 304-2. In the illustrated embodiment, the first multi-valve block 304-1 is configured to deliver a first precursor (precursor 1), such as TiCl4, via two first precursor ALD valves 140-1 and 140-2 connected thereto, and to deliver a second precursor (PreC2), such as SiCl2H2, via two second precursor ALD valves 144-1 and 144-2 connected thereto. The first multi-valve block 304-1 is further configured to deliver a flushing gas, such as N2 or Ar, via a first flushing gas ALD valve 148-1 connected thereto. The second multi-valve block 304-2 is configured to deliver a third precursor (precursor 3), such as NH3, via four precursor ALD valves 220-1, 220-2, 220-3, and 220-4 connected thereto. The second multi-valve block 304-2 is further configured to deliver a flushing gas, such as N2 or Ar, via a second flushing gas ALD valve 148-2 connected thereto. According to an embodiment, the multi-valve assembly 250 configured in this way includes two or more atomic layer deposition (ALD) valves configured to deliver the same precursor of three precursors and a flushing gas. Ten ALD valves are coupled to the illustrated multi-valve assembly 250. However, the embodiment is not limited thereto, and the number of ALD valves may be greater than or less than 10.

[0041] Referring again to Figure 3A, the multi-valve assembly 250 is connected at its bottom to the central area of ​​the top surface of the cover of the deposition chamber 102 (Figure 1). The top surface of the cover is physically located outside the deposition chamber 102. As configured, the multi-valve assembly 250 is configured to position the ALD valves directly above the central area of ​​the substrate inside the deposition chamber 102. The precursor and flushing gas ALD valves are connected to the multi-valve assembly 250 located outside the thin film deposition chamber 102, and the multi-valve assembly 250 is configured to act as a hub to receive the precursor and flushing gas and introduce them into the thin film deposition chamber 102 (Figure 2) via individual ALD valves. Inside the processing chamber, a nozzle 108 (Figure 1) is attached to the cover, which is connected to a gas distribution plate 112 (Figure 1), also known as a showerhead, configured to diffuse the precursor onto the substrate 120 (Figure 1) on the base 116 (Figure 1).

[0042] Figure 3B shows a perspective view of one of the multiple valve blocks illustrated in Figure 3A according to an embodiment, which are configured to be coupled in parallel to a plurality of ALD valves on a common gas distribution plate. The multiple valve blocks, which may be solid blocks in which conduits or channels are formed, are positioned outside the thin-film deposition chamber 102 (Figures 1 and 2) and act as hubs to receive a first of the precursors and guide the precursors and flushing gas via internal conduits or channels defined in the multiple valve blocks. Specifically, Figure 3B shows a perspective view of the first multiple valve block 304-1 illustrated in Figure 3A. For clarity, the first multiple valve block 304-1 is shown without attached ALD valves. In reality, the attachment positions of the two first precursor ALD valves 140-1 and 140-2 configured for delivering a first precursor (precursor 1) such as TiCl4, the two second precursor ALD valves 144-1 and 144-2 configured for delivering a second precursor (precursor 2) such as SiCl2H2, and the first purge gas ALD valve 148-1 configured for delivering inert gas are indicated by dotted circles. Each of the attachment positions of the two first precursor ALD valves 140-1 and 140-2 and the two second precursor ALD valves 144-1 and 144-2 includes an inlet (IN), an outlet (OUT), and an inert gas inlet (INERT). Unlike the ALD valve, which is a precursor to the three-port ALD valve described above, the attachment position of the first flushing gas ALD valve 148-1, which is a two-port ALD valve described above, includes an inlet (IN) and an outlet (OUT), while the inert gas inlet is omitted.

[0043] The first multi-valve block 304-1 includes a plurality of gas input ports 308, 312, 316, and 320 for receiving precursors and flushing gases. In the illustrated configuration, similar to the configuration shown in Figures 2 and 3A, input ports 308 and 312 are configured to feed a first precursor (precursor 1), such as TiCl4, and a second precursor (precursor 2), such as SiCl2H2. Additionally, input ports 316 and 320 are configured to feed flushing gases, such as N2 or Ar, for delivery as rapid flushing (RP) and continuous flushing (CP) gases, respectively. Although not shown, the second multi-valve block 304-2 can be similarly configured, but in which a third precursor (precursor 3) is fed to two precursor input ports 308 and 312. Of course, the input ports are not limited to the configuration described, and depending on the number of gases and the number of delivery lines / ALD valves for each gas, there may be additional or fewer input ports.

[0044] Referring again to Figure 3B, after entering input ports 308, 312, 316, and 320, each precursor and flushing gas passes through a separate conduit before being introduced into their respective ALD valves. Each of the precursors enters one of the ALD valves 140-1, 140-2, 144-1, and 144-2 via a separate inlet. The CP gas enters one of the precursor ALD valves 140-1, 140-2, 144-1, and 144-2 via a separate flushing gas inlet (INERT). The precursor and CP gas exit through the outlet (OUT) and travel through the outlet conduit 328, then are introduced into the vertically extending central conduit 324, and then exit through the central outlet 332 from the first multi-valve block 304-1, for example through the nozzle 108 (FIG. 1) and the gas distribution plate 112 (FIG. 1) into the deposition chamber 102 (FIG. 1 and 2).

[0045] A central conduit 324, positioned above the central region of substrate 120 (FIG. 1), is configured to combine precursors and flushing gases from multiple ALD valves. The precursors and flushing gases are then introduced into the deposition chamber via, for example, nozzle 108 (FIG. 1), and subsequently distributed by a gas distribution plate 112 (FIG. 1). Therefore, in the described configuration, the central conduit 324 is the final conduit before the precursors and flushing gases are introduced into the deposition chamber 102. The inventors have found that the configuration of the multi-valve assembly 250 (FIG. 3A), including its centrally located position and the arrangement of the conduits, can be critical for achieving various advantages, including rapid precursor delivery time. For example, the inventors have found that the vertical position of the ALD valves, vertically positioned above the surface of substrate 120 (FIG. 1), is critical for achieving an exposure time of less than 1 second to substantially saturate the substrate surface with each precursor. As described herein, substantial saturation refers to a condition where increasing exposure time does not substantially increase the growth rate. For example, for various materials, increasing exposure time by 20%, 50%, 100%, or any of these values, will not cause an increase in growth rate exceeding 1%, 2%, 5%, 10%, or any of these values.

[0046] Specifically, referring again to Figure 3B, among various design parameters, the inventors have found that the vertical position of the outlet (OUT) of the precursor and flushing gas ALD valve (which defines the distance from the ALD valve to the central outlet 332 and the diameter of the central conduit 324, the combination of which defines the conduction of the central conduit 324) is crucial for reducing the residence time of the precursor from the ALD valve to the substrate. To reduce the precursor residence time, according to various embodiments, the vertical position of the outlet (OUT) of the precursor and flushing gas ALD valve relative to the central outlet 332 (defined by the length of the central conduit 324) is less than 5'', 4'', 3'', 2'', 1'', or has a value within the range defined by any of these values. Additionally, the central conduit 324 has a diameter greater than 0.2'', 0.30'', 0.40'', 0.50'', 0.60'', or a value within the range defined by any of these values. In the illustrated embodiment, the central conduit 324 has a length of approximately 3.7'', and the outlet of each of the precursor ALD valves 140-1, 140-2, 144-1, and 144-2 is located within approximately 2.0'' of the central outlet 332. Because the OUT of the first flushing ALD valve 148-1 for introducing rapid flush (RP) is located above the precursor ALD valves 140-1, 140-2, 144-1, and 144-2, the OUT of the first flushing ALD valve 148-1 is located further, within approximately 4'' of the central outlet 332. Additionally, the central conduit 324 has a diameter of 0.375''.

[0047] The inventors have further discovered that the length of the outlet conduit 328 (which defines the conduction from the outlet (OUT) of the ALD valve to the central conduit 324) and the diameter of the outlet conduit 328 (which, in combination, defines the conduction of the outlet conduit 328) can also be critical for reducing the residence time of the precursor from the ALD valve to the substrate. To reduce precursor residence time, according to various embodiments, the outlet conduit 328 can be designed to have a length less than 2'', 1.5'', 1'', 0.5'', or any of the values ​​defined therein. Additionally, the outlet conduit 328 has a diameter greater than 0.10'', 0.20'', 0.30'', 0.40'', or any of the values ​​defined therein. In the illustrated example, the length and diameter of the outlet conduit 328 are 0.86'' and 0.216'', respectively.

[0048] Referring again to Figure 3B, the inventors have further discovered that the number of bends in the total length of the conduits between input ports 308, 312, 316, 320 and the central outlet 332 can be kept low to improve the conduction of the conduits and thereby improve the gas delivery time to the substrate. According to various embodiments, the number of bends does not exceed three, two, or one. In the illustrated example, the number of bends in the total length of each of the conduits between input ports 308, 312, 316, 320 and the central outlet 332 does not exceed four; that is, there are two or three bends between each input port 308, 312, 316, 320 and the respective IN of ALD valves 140-1, 140-2, 144-1, 144-2, 148-1, and one bend between each OUT of the ALD valve and the central outlet 332.

[0049] Furthermore, the inventors have discovered that it is advantageous to closely align the central vertical axis of the multi-valve block 250, the central conduit 324, and / or the central outlet 332 (FIG. 3B) with the center position of the cover and / or substrate of the deposition chamber, so as to minimize the gas residence time and / or gas delivery time to the substrate. According to various embodiments, the lateral offset between the central vertical axis of the multi-valve block 250, the central conduit 324, and / or the central outlet 332 (FIG. 3B) and the center position of the cover and / or substrate of the deposition chamber does not exceed 2'', 1'', 0.5'', 0.25'', or has a value within the range defined by any of these values.

[0050] Referring again to Figure 3B, multiple ALD valves configured to deliver the same gas (precursor or flushing gas) can be connected upstream to a common port among inlet ports 308, 312, 316, and 320. After being fed into individual inlet conduits and individual ALD valves, each gas is delivered to deposition chamber 102 (Figures 1 and 2) via a common central conduit 324. Two or more atomic layer deposition (ALD) valves connected to the first multi-valve block 304-1 are advantageously configured to supply the same gas to the deposition chamber simultaneously or sequentially.

[0051] Figure 3C shows a perspective view of an ALD valve configured to couple to one of the multiple valve blocks illustrated in Figure 3B, according to an embodiment. According to the embodiment, the illustrated ALD valve 350 may represent one of the first precursor ALD valves 140-1, 140-2, the second precursor ALD valves 144-1, 144-2, and the flushing gas ALD valve 148-1 described above with respect to Figures 3A and 3B. The illustrated ALD valve 350 is divided into an upper portion 354 and a lower portion 358, which are coupled to a multiple valve block such as that illustrated in Figure 3B. The upper portion 354 and the lower portion 358 are connected by a pneumatic coupling portion 362. The illustrated ALD valve 350 further includes a thermocouple unit 366 for temperature sensing and / or control. The upper portion 354 includes a pneumatic actuator assembly comprising a solenoid pilot valve and various other components. The lower portion 358 includes a valve body comprising a valve body, a valve diaphragm, and a valve seat, as well as various other components. The position of the valve diaphragm can be monitored by a position sensor. As configured, the ALD valve 350 can be configured as a pilot-operated diaphragm solenoid valve. As described herein, a pilot-operated solenoid valve refers to a solenoid valve that uses the pressure differential of the medium at the valve port to open and close the valve. A pilot-operated diaphragm solenoid valve uses a small chamber directly above the diaphragm to assist valve operation. Process fluid is allowed to enter the chamber through a small orifice in the inlet port, and in a normally closed valve, the diaphragm is compressed and forces are applied to the seat to maintain a closed seal. Once current is applied to the pilot solenoid, the diaphragm is pulled upward against spring pressure, causing the pilot fluid in the chamber to return through an orifice in the inlet, where it rejoins the main flow through the valve body. Pilot-operated diaphragm solenoid valves can operate at high speeds (response time less than 30 milliseconds). Furthermore, compared to direct-acting solenoid valves, pilot-operated diaphragm solenoid valves offer relatively higher flow rates, can operate over higher pressure and temperature ranges, and consume less power.

[0052] Figure 3D is an example experimental diagram illustrating various signals associated with the actuation of an ALD valve, such as that illustrated in Figure 3C, according to the embodiment. The experimental diagram illustrates, by way of example, curve 370-1 corresponding to the command signal electronically sent from the valve controller to the ALD valve, curve 370-2 corresponding to the electrical distribution of the solenoid pilot valve, curve 370-3 corresponding to the diaphragm position, and curve 370-4 corresponding to the electronic position sensor signal. In operation, when the command signal is given by the valve controller as shown in curve 370-1, the pilot valve is actuated, as shown in curve 370-2. After the solenoid pilot valve is fully open, the diaphragm changes its position and the valve opens, as shown in curve 370-3. As shown in Figure 3D, the actuation speed is defined by the duration between the valve opening and the pilot valve opening, as verified by the sensor. After the valve is fully open, the position sensor senses the position of the diaphragm and determines that the valve has completed its opening. As defined herein and illustrated in Figure 3D, the response time of the ALD valve corresponds to the time elapsed from when the command signal is electronically sent from the valve controller to the ALD valve until the ALD valve is fully open or closed, as sensed by a diaphragm position sensor. For the ALD valve described, the actuation speed is less than 5 ms and the response time is less than 15 ms.

[0053] As discussed above, the precursor delivery system disclosed herein allows for a combined flow rate of precursors via two or more ALD valves that is significantly higher than the flow rate of conventional thin film deposition systems, thereby significantly reducing ALD cycle time. Furthermore, the inventors have discovered that the duration of ALD cycles can be reduced through various other modifications disclosed herein.

[0054] The inventors have discovered that reducing the distance between the outlet (OUT) of the ALD valve and the substrate (valve-substrate distance) can advantageously and critically further reduce the time required for sufficient substantial surface saturation and / or ALD cycle time. Therefore, according to an embodiment, the ALD valve is positioned directly above a cover portion of each processing station, which in turn is positioned above a corresponding base. The ALD valve is positioned relative to the main surface of the substrate (FIG. 1) at a distance defined by, for example, 30'', 25'', 20'', 15'', 10'', 5'', 3'', or any of these values, or a distance defined by, 50 cm, 40 cm, 30 cm, 20 cm, 10 cm, 5 cm, or any of these values. The valve-substrate distance can be the sum of the vertical distance between the outlet (OUT) of the precursor ALD valve as described above with respect to the central outlet 332 (Figure 3B) at the bottom of the defining central conduit 324 (Figure 3B) and the vertical distance from the central outlet 332 to the surface of the substrate.

[0055] The inventors have discovered that the piping configuration between the actuator and the solenoid of the pilot valve in an ALD valve can further affect the ALD valve response time. Specifically, the inventors have discovered that reducing the piping length is beneficial for reducing valve response time. The inventors have discovered that by reducing the piping length (which may be 1 / 8'' or 1 / 4'' in diameter) between the actuator assembly of the ALD valve in the upper portion 354 (FIG. 3C) and the valve body portion in the lower portion 358 (FIG. 3C), and more specifically by reducing, for example, the distance between the solenoid in the actuator assembly and the diaphragm in the valve body, the response time can be further reduced. According to embodiments, this distance is less than 5'', 4'', 3'', 2'', 1'', 0.5'', or has a value within the range defined by any of these values, or 10 cm, 8 cm, 6 cm, 4 cm, 2 cm, 1 cm, or a value within the range defined by any of these values. For example, by reducing the length from 36 inches to 3 inches, it was found that the response time could be reduced by up to 10 ms.

[0056] The ALD valve configured in this way according to the embodiments is configured to operate with significantly improved actuation speed and response time compared to conventional valves in ALD systems. According to various embodiments, the actuation speed of the ALD valve can be reduced to less than 10 ms, 5 ms, 4 ms, 3 ms, 2 ms, or any value defined therein, and the response time can be reduced to less than 30 ms, 25 ms, 20 ms, 15 ms, 10 ms, 5 ms, or any value defined therein. These values ​​can be achieved, for example, with an actuation pressure of 50 to 90 psig.

[0057] The inventors have also discovered that the valve coefficient should be optimized to increase the flow rate at a given pressure drop in order to improve the response time. According to various embodiments, the ALD valve has a valve flow coefficient (Cv) exceeding a value within a range defined by 0.20, 0.30, 0.40, 0.50, 0.60, 0.70, or any of the equivalent values.

[0058] In some cases, the ALD valve according to embodiments is advantageously configured to operate at high temperatures. For example, when it is necessary to introduce a precursor (e.g., a vaporized liquid precursor) into a deposition chamber at high temperatures, it may be advantageous to heat the corresponding ALD valve and / or multiple valve blocks to a temperature above room temperature, for example, to match the temperature of the precursor introduced into the multiple valve blocks. According to various embodiments, the ALD valve is configured to operate at valve temperatures exceeding 80°C, 100°C, 150°C, 200°C, 250°C, or any of the above values. Specifically, referring back to FIG. 3C, the lower portion 358 may include a heater for heating the valve body portion. In these embodiments, the coupling portion 362 may include a heat-insulating housing portion to reduce the heating effect on the upper portion 354, since heating may adversely affect the operation of the actuator assembly, for example, reducing the repeatability of the actuation speed.

[0059] According to various embodiments, each of the ALD valves is configured for open / close cycles exceeding a range defined by 2 million, 5 million, 10 million, 20 million, 50 million, 100 million, or any equivalent value, prior to replacement or repair. When a single ALD valve is used for a given precursor, preventative maintenance can be performed after this number of cycles. Advantageously, when two or more valves are used alternately to introduce a given precursor, the ALD valve life per wafer processed can be increased proportionally. It should be understood that increasing the duration between preventative maintenance or chamber opening can significantly improve productivity and reduce production costs.

[0060] Figure 4 illustrates an example deposition chamber in which various embodiments can be implemented. Figure 4 shows a perspective view of the top exterior portion of a deposition chamber 400 comprising multiple processing stations according to an embodiment, each configured to deliver precursors using two or more ALD valves connected in parallel to a common gas distribution plate. Each processing station is configured, for example, in a similar manner to that described above with respect to Figure 1, and includes a separate cover portion. Referring back to Figure 1, after each of the individual stations in the MFC, each of the gas delivery lines branches into multiple lines at a separate manifold 136. Each of the branch lines can feed a separate gas to one of the processing stations. The illustrated processing chamber comprises one or more processing stations, each configured to process a substrate on a support, such as a base, under process conditions in a similar manner to that described above with respect to Figure 1. Each processing station is configured to process the substrate under a single process condition including process temperature and process pressure. In the illustrated embodiment, there are four processing stations having corresponding cover portions 112-1, 112-2, 112-3, and 112-4. Each of the multiple valve blocks 250-1, 250-2, 250-3, and 250-4 is attached to the center of each of the cover portions 112-1, 112-2, 112-3, and 112-4. Each of the multiple valve blocks 250-1, 250-2, 250-3, and 250-4 can be configured in a similar manner to that described above with respect to Figures 3A to 3D; for brevity, the details are not repeated herein. Furthermore, the gas lines for delivering the same gas to the multiple valve blocks 250-1, 250-2, 250-3, and 250-4 branch off from the common manifold 136 shown, which is similar to the manifold 136 described above with respect to Figure 1. According to the embodiments, the illustrated deposition chamber is therefore configured to introduce one or more precursors for each processing station using two or more atomic layer deposition (ALD) valves, each of which is configured to supply precursors and / or flushing gas. Although the illustrated processing chamber is a multi-station processing chamber, it should be understood that the embodiments disclosed herein are not limited thereto and can be implemented in any suitable single-wafer or multi-wafer processing chamber. [Thin film deposition method using two or more valves for the same precursor]

[0061] Various advantageous methods for depositing thin films can be implemented using the thin film deposition system described above. According to various embodiments, a method of depositing a thin film includes alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber. Exposing the substrate includes introducing one of the precursors into the thin film deposition chamber via two or more atomic layer deposition (ALD) valves, each configured to supply one of the precursors.

[0062] Figure 5A illustrates an example precursor delivery sequence for an ALD cycle for thin film deposition according to some embodiments, including an exposure sequence of precursors using two or more ALD valves in one cycle. The illustrated method for depositing a thin film includes alternately exposing a substrate to a plurality of precursors (precursor 1, precursor 2) in a thin film deposition chamber. Alternately exposing the substrate includes introducing a first of the precursors (precursor 1) into the thin film deposition chamber by independently actuating two or more first ALD valves connected in parallel to a common gas distribution plate to supply the first of the precursors into the thin film deposition chamber. Independently actuating two or more first ALD valves includes simultaneously opening two or more first ALD valves for at least a portion of the time during the introduction of the first of the precursors into the thin film deposition chamber.

[0063] The described ALD cycle includes a first sub-cycle comprising exposure cycles 500A and 500C for exposing the first precursor (precursor 1) to the substrate, and a second sub-cycle comprising exposure cycles 500C and 500D for exposing the substrate to the second precursor (precursor 2). The described example shows that during the first sub-cycle, two first precursor ALD valves 140-1 and 140-2 (FIG. 1) are used to introduce precursor 1 from two first precursor sources 120-1 and 120-2 (FIG. 1). Two additional precursor ALD valves actuating precursor 1 are indicated by exposure cycles 500A and 500B, which respectively represent gas flow through the first precursor ALD valves 140-1 and 140-2. Exposure cycles 500A and 500B involve introducing precursor 1 into the deposition chamber using two first precursor ALD valves 140-1 and 140-2, respectively, thereby exposing the substrate to first precursor (precursor 1) pulses 504-1 and 504-2. Following precursor 1 pulses 504-1 and 504-2, rapid flushing (RP) gas is introduced into the deposition chamber using a first flushing gas ALD valve 148-1, thereby exposing the substrate to first RP pulses 508-1 and 508-2. As described, actuating the two first precursor ALD valves 140-1 and 140-2 involves simultaneously opening both first precursor ALD valves 140-1 and 140-2 at least temporarily for at least a portion of the time during the introduction of precursor 1 into the thin film deposition chamber. Therefore, the first precursor pulses 504-1 and 504-2 overlap at least partially in time, or substantially or completely in time, as illustrated. In the illustrated example, the first RP pulses 508-1 and 508-2 overlap completely because they are provided using the same first flushing gas ALD valve 148-1. However, when different ALD flushing valves are used, the flushing pulses 508-1 and 508-2 may overlap partially in time, or substantially or completely in time, as illustrated.

[0064] Alternatively or as illustrated in the examples, during the second sub-cycle, precursor 2 is introduced from two second precursor sources 124-1, 124-2 (FIG. 1) using two second precursor ALD valves 144-1, 144-2, which can be configured in a similar manner as described above. Actuation of two additional ALD valves is indicated by exposure cycles 500C and 500D, which respectively represent gas flow through the second precursor ALD valves 144-1 and 144-2. Exposure cycles 500C and 500D involve exposing the substrate to second precursor (precursor 2) pulses 516-1 and 516-2, respectively, by introducing precursor 2 into the deposition chamber using the second precursor ALD valves 144-1 and 144-2. Following precursor 2 pulses 516-1 and 516-2, the substrate is exposed to second RP pulses 520-1 and 520-2 by introducing rapid flushing (RP) gas into the deposition chamber using a second flushing gas ALD valve 148-2. As described, actuating the two second precursor ALD valves 144-1 and 144-2 includes simultaneously opening both second precursor ALD valves 144-1 and 144-2 at least temporarily for at least a portion of the time during the introduction of precursor 2 into the thin film deposition chamber. Therefore, the second precursor pulses 516-1 and 516-2 overlap at least partially, or substantially or completely, as described. In the illustrated example, the second RP pulses 520-1 and 520-2 completely overlap because they are provided using the same second flushing gas ALD valve 148-2. However, when using different ALD flush valves, flush pulses 520-1 and 520-2 may overlap partially or substantially or completely, as described.

[0065] As described above, each of the precursor ALD valves is a three-port valve, and in some embodiments, a continuous flushing (CP) gas (e.g., an inert gas) can be flowed through the ALD valve while the substrate is exposed to the first and / or second precursor. The inventors have discovered that allowing CP gas flow during ALD cycles can advantageously reduce the exposure time of the RP pulse, thereby further improving the cycle time. In the illustrated embodiments, exposure cycles 500A to 500D further include the continuous exposure of the substrate to CP 512-1, 512-2, 524-1, and 524-2 using an inert gas during and after exposure to one or both of the first and second precursors. The amount of rapid flushing is higher than that of CP.

[0066] Advantageously, as described above, one or both of the first precursor (precursor 1) and the second precursor (precursor 2) can be introduced into the thin film deposition chamber via each of two or more precursor ALD valves 140-1, 140-2, 144-1, and 144-2. Therefore, one or both of the first precursor and the second precursor can be introduced into the thin film deposition chamber at a combined flow rate of two or more precursor ALD valves. Thus, the exposure time to saturation for one or both of the first and second precursors can be substantially reduced. For example, according to some embodiments, for a given precursor, the exposure time can be reduced by more than 20%, 40%, 60%, 80%, or a value within the range defined by any of these values, compared to the exposure time to saturation using only one precursor ALD valve. Surface saturation can be inferred, for example, based on the deposition rate as described above. That is, compared to the ALD method that uses only one ALD valve for a given precursor, substantially the same thickness can be achieved while reducing the exposure time of the precursor by more than 20%, 40%, 60%, 80%, or any of these values.

[0067] According to various embodiments, by employing two or more precursor ALD valves, the exposure time of one or both of the first precursor (precursor 1) and the second precursor (precursor 2) can be maintained at less than 1.0 s, 0.8 s, 0.6 s, 0.4 s, 0.2 s, 0.1 s, or a value within the range defined by any of these values. The thin film deposition system is configured to introduce one or both of the first and second precursors at a combined flow rate using two or more precursor ALD valves, such that the surface of the substrate is substantially saturated, for example, to a saturation level greater than 40%, 60%, 80%, or a value within the range defined by any of these values, despite a relatively short exposure time. In embodiments where rapid rinsing is performed after exposure to the precursors, the duration of one or both of the first and second sub-cycles can be less than 1.0 s, 0.8 s, 0.6 s, 0.4 s, 0.2 s, 0.1 s, or a value within the range defined by any of these values. By reducing the exposure time of one or both of the first and second precursors, the duration of one or both of the first and second sub-cycles can be reduced, thereby reducing the total ALD cycle time. According to an embodiment, the duration of the total ALD cycle is less than 2.0 seconds, 1.5 seconds, 1.0 seconds, 0.5 seconds, or a value within the range defined by any of these values.

[0068] Figure 5B illustrates, by way of example only, a specific example precursor delivery sequence for the cyclic deposition of TiN or ALD using TiCl4 and NH3 according to the method described above with respect to Figure 5A. The above-described exposure cycle may correspond to exposure cycles 500A and 500B described above with respect to Figure 5A, and may represent a TiCl4 exposure cycle performed via first precursor ALD valves 140-1 and 140-2. Similarly, the below-described exposure cycle may correspond to exposure cycles 500C and 500D described above with respect to Figure 5A, and may represent an NH3 exposure cycle performed via second precursor ALD valves 144-1 and 144-2. A processing station similar to that described above with respect to Figure 1 or Figure 4 may be used. For example, the treatment station can be configured to deliver TiCl4 via two first precursor ALD valves 140-1, 140-2 (Figure 2) and NH3 via four second precursor ALD valves 220-1, 220-2, 220-3, 220-4 (Figure 2). Each of the precursor ALD valves 140-1, 140-2, 220-1, 220-2, 220-3, 220-4 (Figure 2) is also configured to allow a continuous flow of purging (CP) gas (e.g., inert gas) through these precursor ALD valves. The treatment station can also be configured to deliver rapid purging (RP) gas, such as inert gas, via two purging gas ALD valves 148-1, 148-2. For example, the treatment station can also be configured to deliver first RP pulses 508-1 and 508-2 via one of the first precursor pulses 504-1 and 504-2 (Figure 5A) after one of them, and second RP pulses 520-1 and 520-2 via the other of the second RP pulses 148-2 (Figure 5A) after one of them. The illustrated table shows typical parameters for a given treatment station and flow conditions for different ALD valves. In this example, by simultaneously delivering TiCl4 through two precursor ALD valves 140-1 and 140-2 (Figure 2), delivering NH3 through four precursor ALD valves 220-1, 220-2, 220-3, and 220-4 (Figure 2), and delivering N2 through one of two purge gas ALD valves 148-1 and 148-2, combined flow rates of 220 sccm and 8000 sccm can be achieved for TiCl4 and NH3 respectively during each sub-cycle. Combining the 5000 sccm flow rate of each of the purge gas ALD valves 148-1 and 148-2, a TiCl4 exposure sub-cycle time of 0.5 seconds and an NH3 exposure sub-cycle time of 0.35 seconds can be achieved, for a total ALD cycle time of 1.05 seconds.

[0069] Advantageously, by allowing relatively high amounts of precursor and CP gas to flow through two or more precursor ALD valves, relatively high chamber pressures can be achieved without reducing the pumping power of the deposition chamber. The inventors have discovered that when a substrate has a relatively high surface area, for example due to a relatively high areal density of a high aspect ratio structure, thin films with different properties at different portions of the exposed surface can be produced using ALD process formulations by thin film coating of the exposed surface. These ALD process formulations are developed based on the characteristics of films formed on flat or unpatterned substrates or substrates with relatively low surface area or low areal density and a high aspect ratio structure. For example, in a high aspect ratio structure in a substrate with a relatively high areal density, conformability or stepped coverage, as described above, may be significantly poorer. Other properties that may also differ at different portions of the exposed surface include film stoichiometry, surface roughness, resistivity, and film density, to name a few. Without being bound by any theoretical constraints, one reason for the low uniformity of characteristics can be the significantly increased exposed surface area of ​​the substrate compared to a planar substrate. Due to the increased exposed surface area, different portions of the exposed surface can receive different amounts of precursor flux, allowing different amounts of precursor to adhere to different portions of the exposed surface. Using only a simplified example, when hundreds of grains, each with approximately 1 × 10¹⁰ or more transistors, are formed on a 300 mm semiconductor substrate, and each transistor has one or more vias with a diameter of 10 to 100 nm and an aspect ratio of 1 to 100, the surface area exposed to the precursor during thin film deposition can exceed the surface area of ​​the corresponding unpatterned substrate by 10, 100, 1000, or more. Furthermore, the local deposition conditions can differ at different portions of the exposed surface. For example, the local pressure inside a deep trench or via can differ from, for instance, lower than, the pressure outside the deep trench or via. In addition, under vacuum conditions, because gas molecules collide more with the sidewalls of the trenches or through holes, the upper part of the deep trenches or through holes may adsorb a higher amount of precursor molecules due to the higher flux.

[0070] According to the various embodiments described herein, by utilizing higher deposition pressures, the inventors have discovered that the deposition methods described herein are particularly advantageous for forming TiSiN and / or TiAlN films with high uniformity at different portions of the exposed surface regarding various physical properties, including conformality, step coverage, film stoichiometry, surface roughness, resistivity, and film density (to name a few). Therefore, TiSiN and / or TiAlN films formed according to the deposition methods disclosed herein exhibit high uniformity regarding one or more of these physical properties at both the local (e.g., within trenches or vias) and overall (e.g., within the wafer) levels. Therefore, the deposition method according to the embodiments is particularly advantageous for forming thin films containing TiSiN and / or TiAlN on a substrate containing surface morphology, such that the ratio of the surface area of ​​the semiconductor substrate exposed to one or more vapor deposition cycles to the surface area of ​​the corresponding unpatterned semiconductor substrate exceeds 2, 5, 10, 20, 50, 100, 200, 500, 1000, or has a ratio within or higher than any of these values.

[0071] Alternatively or additionally, the deposition method according to the embodiments is particularly advantageous for forming thin films on substrates comprising high aspect ratio structures having an aperture width less than 1 micrometer, 500 nm, 200 nm, 100 nm, 50 nm, 20 nm, or any of these values; an aspect ratio exceeding 5, 10, 20, 50, 100, 200, or any of these values; and an area density such that the surface area is greater than the surface area of ​​a planar substrate as described above. Substrates having such surface morphology can be conformally coated with thin films comprising TiSiN and / or TiAlN according to the embodiments, having a stepped coverage as defined above exceeding 50%, 60%, 70%, 80%, 90%, 95%, or any of these values ​​or higher. As discussed above, the inventors have discovered that these results can be achieved by optimizing the process conditions for conformally coating substrates with high aspect ratio structures having relatively high area density, according to the embodiments. The inventors have discovered that these results can be achieved, in particular, by controlling the reaction chamber pressure or precursor partial pressure, deposition rate, temperature or pressure of the precursor introduced into the reaction chamber, precursor flow rate, and exposure time (to name a few).

[0072] The inventors have discovered that, according to embodiments, when coating a substrate with a high aspect ratio structure having a relatively high area density, the relatively high total or partial pressure achieved by simultaneously activating two or more precursor ALD valves can improve conformability and stepped coverage. Without being bound by any theory, such improvements can be particularly associated with mitigating the effects of locally reduced precursor partial pressure within high aspect ratio vias or trenches. According to embodiments, the total or partial pressure of any of the individual precursors (e.g., Ti precursor, N precursor, and / or Si and / or Al) during substrate exposure for a given subcycle can be 1.0 to 3.0 Torr, 3.0 to 5.0 Torr, 5.0 to 7.0 Torr, 7.0 to 9.0 Torr, 9.0 to 11.0 Torr, 11.0 to 13.0 Torr, 13.0 to 15.0 Torr, or a pressure within the range defined by any of these equivalent values. In each of the exposures to Ti precursors, N precursors, and / or Si and / or Al precursors, the respective precursor may constitute 1% to 2%, 2% to 5%, 5% to 10%, 10% to 20%, 20% to 50%, 50% to 100%, or a percentage within the range defined by any of these values, of the total gas molecules in the reaction chamber. The inventors have discovered that, in some cases, when the total pressure or partial pressure exceeds these values, the stepped coverage may begin to degrade, etc.

[0073] The inventors have discovered that, to a certain extent, in order to achieve relatively high yields while delivering relatively high quantities of precursors to the reaction chamber for deposition at relatively high total or partial pressures, the flow rate of the precursors entering the reaction chamber should be significantly higher than the flow rate used in process conditions for forming thin films on flat substrates and / or substrates with low (e.g., <1) aspect ratio structures. This high flow rate can be achieved by increasing one or both of the temperature or pressure of the precursors before introducing them into the reaction chamber. For example, for precursors in liquid form under manufacturing conditions, the precursor vial can be heated to temperatures above room temperature, such as 30°C to 60°C, 60°C to 80°C, 80°C to 100°C, 100°C to 120°C, 120°C to 150°C, or temperatures within the range defined by any of these values, to increase the vapor generation rate. The lower and upper limits of these ranges can be determined in part based on the vapor pressure and decomposition temperature of the precursors, respectively. By way of example, TiCl4 can be heated to approximately 60°C to 80°C. On the other hand, for precursors in gaseous form under manufacturing conditions, high flow rates can be achieved by increasing the gas line pressure to a value much higher than the gas line pressure used for forming thin films on substrates with relatively low surface area or flat substrates and / or substrates with low (e.g., <1) aspect ratio structures. It should be understood that the relatively high flow rates required to achieve the various advantages described herein can depend in particular on the pumping rate, exposure time, and reactor volume. To achieve a suitable flow rate for depositing thin films on substrates with high surface area and / or high aspect ratio structures, the temperature and / or pressure of the precursors, as well as other parameters, can be adjusted so that the flow rate of each of the Ti, N, Si, and Al precursors can be, for example, 100 to 1000 standard cubic centimeters per minute (sccm), 1000 to 2000 sccm, 2000 to 5000 sccm, 5000 to 10,000 sccm, 10,000 to 15,000 sccm, 15,000 to 20,000 sccm, or a value within or higher of any of these values. It should be understood that a suitable flow rate can be particularly dependent on the reactor volume, and some of these flow rates are suitable for single-wafer reactors with a volume of about 1 to 2 liters.

[0074] In the ALD cycle illustrated in Figure 5A, each of the two or more ALD valves used to deliver a given precursor or purge gas is actuated during the same period in each sub-cycle. Thus, each of the illustrated exposure cycles 500A to 500D is repeated multiple times in each cycle using the same of the respective ALD valves. Therefore, the sum of the exposure cycles 500A to 500D illustrated in Figure 5A represents a full ALD cycle, and the same cycle can be repeated any number of times. As discussed above, such embodiments offer the advantages of increased flow rate, increased pressure, and rapid cycle time. However, the embodiments are not limited thereto. In other embodiments, different sub-cycles for exposing a given precursor can be performed by using different of the two or more ALD valves, for example, introducing the given precursor into the thin film deposition chamber in different cycles. For example, a first of two or more precursor ALD valves can be used to introduce one of the precursors in a first cycle, while a second of two or more precursor ALD valves can be used to introduce the same precursor in a second cycle. Thus, by way of example, in the precursor sub-delivery system shown in Figure 2, where four precursor ALD valves are configured to deliver NH3, the first and second ALD valves can be used to perform the first cycle to deliver NH3, while the third and fourth ALD valves can be used to perform the second cycle to deliver NH3. Advantageously, by alternating different ALD valves to deliver the precursor, the wear rate of the ALD valves can be reduced, thereby increasing the time between valve replacements or servicing, which in turn reduces downtime of the deposition system. One such example embodiment is illustrated in Figure 6.

[0075] Figure 6 illustrates an example precursor delivery sequence for thin film deposition in two ALD cycles according to some embodiments, including an exposure sequence of precursors using two or more ALD valves connected in parallel to a common gas distribution plate in two or more cycles. The illustrated method for depositing thin films includes alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber. Alternately exposing the substrate includes introducing a first of the precursors (precursor 1) into the thin film deposition chamber by independently actuating two or more first ALD valves connected in parallel to the common gas distribution plate to supply the first of the precursors into the thin film deposition chamber. Independently actuating two or more first ALD valves includes actuating the first of the two or more first ALD valves during a first cycle and actuating the second of the two or more first ALD valves during a second cycle following the first cycle. For brevity, features of the delivery sequence illustrated in Figure 6, which are similar to those of the delivery sequence illustrated in Figure 5A, are omitted below.

[0076] The described ALD cycle includes a first cycle comprising exposure cycles 600A and 600C and a second cycle comprising exposure cycles 600B and 600D. Each of the first and second cycles includes a first sub-cycle for exposing the substrate to a first (precursor 1) precursor and a second sub-cycle for exposing the substrate to a second (precursor 2) precursor. The described example shows that during the first sub-cycle of the first cycle, precursor 1 is introduced from one of the two first precursor sources 120-1 and 120-2 (FIG. 1) using one of the two first precursor ALD valves 140-1 and 140-2, and during the first sub-cycle of the second cycle, precursor 1 is introduced from the other of the two first precursor sources 120-1 and 120-2 (FIG. 1) using the other of the two first precursor ALD valves 140-1 and 140-2. The other two precursor ALD valves for actuating precursor 1 are represented by exposure cycles 600A and 600C, which respectively represent gas flowing through the first precursor ALD valves 140-1 and 140-2 in two separate cycles. Exposure cycles 600A and 600C involve introducing precursor 1 into the deposition chamber using the two first precursor ALD valves 140-1 and 140-2, respectively, thereby exposing the substrate to first precursor (precursor 1) pulses 604-1 and 604-2. After precursor 1 pulses 604-1 and 604-2, the substrate is exposed to first rapid flush (RP) pulses 608-1 and 608-2 to introduce RP gas into the deposition chamber using the first flush gas ALD valve 148-1. Unlike the sequence described above regarding Figure 5A, actuating the two first precursor ALD valves 140-1 and 140-2 does not involve simultaneously or overlapping the opening of both first ALD valves 140-1 and 140-2. In fact, actuating the two first ALD valves 140-1 and 140-2 occurs in two separate ALD cycles. Similarly, the first RP pulses 608-1 and 608-2 do not overlap because they are executed in two separate ALD cycles.

[0077] Alternatively or as further illustrated in the examples, during the second sub-cycle of the first cycle, precursor 2 is introduced from one of the two second precursor sources 124-1, 124-2 (Figure 1) using one of the two second precursor ALD valves 144-1, 144-2, and during the second sub-cycle of the second cycle, precursor 2 is introduced from the other of the two second precursor sources 124-1, 124-2 (Figure 1) using the other of the two second precursor ALD valves 144-1, 144-2. The other two ALD valves actuating precursor 2 are indicated by exposure cycles 600B and 600D, which respectively represent gas flowing through second precursor ALD valves 144-1 and 144-2 in two separate cycles. Exposure cycles 600B and 600D include first precursor (precursor 1) pulses 604-1 and 604-2, respectively, to expose the substrate to precursor 2 by introducing precursor 2 into the deposition chamber using two second precursor ALD valves 144-1 and 144-2. Following precursor 2 pulses 616-1 and 616-2, rapid flush (RP) gas is introduced into the deposition chamber using a second ALD flush valve 148-2, exposing the substrate to second RP pulses 620-1 and 620-2. Unlike the sequence described above with respect to Figure 5A, actuating the two second precursor ALD valves 144-1 and 144-2 does not involve simultaneously or overlapping the opening of both second ALD valves 144-1 and 144-2. In fact, actuation of the two second ALD valves 144-1 and 144-2 is performed in two separate ALD cycles. Similarly, the second RP pulses 620-1 and 620-2 do not overlap because they are executed in two separate ALD loops.

[0078] It should be understood that in a semiconductor manufacturing environment, the costs of scheduled and unscheduled downtime and production interruptions due to component maintenance or replacement can be substantial. Because ALD valves used for depositing a single film may be actuated hundreds or even thousands of times, the costs of scheduled and unscheduled downtime due to ALD valve wear and failure can be very high. The inventors have discovered that using two or more different ALD valves 140-1, 140-2, 144-1, 144-2, 148-1, 148-2 as described above, exposed to a given precursor (e.g., precursor 1, precursor 2) in different cycles, as shown in Figure 6, can advantageously increase the intervals between ALD valve maintenance or replacement. By using such a method, the frequency of maintenance or preventative maintenance of the deposition system can be substantially reduced.

[0079] In the ALD cycles illustrated in Figures 5A and 6, two or more ALD valves are used to deliver a given precursor or purge gas in continuous pulses within a given sub-cycle of the ALD cycle. However, the embodiments are not limited to this. In other embodiments, two additional ALD valves may be used to deliver a given precursor in multiple pulses within a given sub-cycle. In these embodiments, the exposure sequence may be similar to the exposure sequence described with respect to Figure 5A, but multiple back-to-back pulses (without intervention exposure to different precursors) can expose the substrate to a given precursor, which can be performed in the presence of continuous purging. For example, using a precursor delivery system configured with four ALD valves similar to those shown in Figure 2 to deliver NH3, a first pulse of NH3 can be delivered using a first ALD valve and a second ALD valve, while a second pulse of NH3 can be delivered using a third ALD valve and a fourth ALD valve. The first pulse and the second pulse may alternate at least once during the same sub-cycle. One such example embodiment is illustrated in Figure 7.

[0080] Figure 7 illustrates an example precursor delivery sequence for ALD cycles of thin film deposition according to some embodiments, including a precursor exposure sequence in which two or more ALD valves connected in parallel to a common gas distribution plate are used in one cycle to deliver a plurality of pulses of precursor. The illustrated method of thin film deposition includes alternatingly exposing a substrate to a plurality of precursors in a thin film deposition chamber. Alternating exposure of the substrate includes introducing a first of the precursors (precursor 1) into the thin film deposition chamber by independently actuating two or more first ALD valves connected in parallel to the common gas distribution plate to supply the first of the precursors to the thin film deposition chamber. Independently actuating two or more first ALD valves includes exposing the substrate to a plurality of pulses by alternately opening different of the two or more first ALD valves during the same period in the cycle. For the sake of brevity, features of the delivery sequence illustrated in Figure 7, which are similar to those of the delivery sequence illustrated in Figure 5A, are omitted below.

[0081] Similar to the manner described above with respect to Figure 5A, the illustrated ALD cycle includes a first sub-cycle comprising exposure cycles 700A and 700C for exposing the substrate to a first precursor (precursor 1), and a second sub-cycle comprising exposure cycles 700B and 700D for exposing the substrate to a second precursor (precursor 2). However, unlike the sequence described with respect to Figure 5A, the illustrated example shows that during the first sub-cycle, two first precursor ALD valves 140-1, 140-2 (Figure 1) are used to introduce precursor 1 from two first precursor sources 120-1, 120-2 (Figure 1) with a plurality of pulses 704-1, 704-2. The other two ALD valves actuating precursor 1 are represented by exposure cycles 700A and 700B, which respectively represent gas flow through the first precursor ALD valves 140-1 and 140-2. Exposure cycles 700A and 700B involve introducing precursor 1 into the deposition chamber using two first precursor ALD valves 140-1 and 140-2, respectively, thereby exposing the substrate to the first precursor (precursor 1) with a plurality of precursor 1 pulses 704-1 and a plurality of precursor 1 pulses 704-2. Pulses 704-1 and 704-2 may be alternated as described. After the plurality of precursor 1 pulses 704-1 and 704-2, the substrate is exposed to first rapid rinse (RP) pulses 708-1 and 708-2 in a manner similar to the sequence described above with respect to FIG. 5A. As described, actuating the two first precursor ALD valves 140-1 and 140-2 involves alternately opening the two first precursor ALD valves 140-1 and 140-2 to alternately deliver pulses 704-1 and 704-2. Therefore, precursor 1 pulse 704-1 and precursor 1 pulse 704-2 do not overlap, as explained.

[0082] Alternatively or as illustrated in the examples, the second sub-cycle includes exposure cycles 700C and 700D to introduce precursor 2 from two second precursor sources 124-1 and 124-2 (FIG. 1) using two second precursor ALD valves 144-1 and 144-2, which can be configured in a similar manner as described above. Two additional precursor ALD valves for actuation of precursor 2 are indicated by exposure cycles 700C and 700D, which respectively represent gas flow through second ALD valves 144-1 and 144-2. Exposure cycles 700C and 700D involve introducing precursor 2 into the deposition chamber using the two second precursor ALD valves 144-1 and 144-2, respectively, causing the substrate to be exposed to the second precursor (precursor 2) with a plurality of precursor 2 pulses 716-1 and a plurality of precursor 2 pulses 716-2, respectively. Pulses 716-1 and 716-2 can be alternated. Following precursor 2 pulses 716-1 and 716-2, the substrate is exposed to rapid rinsing (RP) gas by second RP pulses 720-1 and 720-2 in a manner similar to the sequence described above with respect to Figure 5A. As explained, actuating the two second precursor ALD valves 144-1 and 144-2 involves alternately opening the two second precursor ALD valves 144-1 and 144-2 to alternately deliver pulses 716-1 and 716-2. Therefore, precursor 2 pulses 716-1 and 716-2 do not overlap, as explained.

[0083] Advantageously, by alternating the different pulses of the precursors in the ALD valves to deliver the different pulses, the amount of overhead time can be reduced, for example, by sending a command signal for one valve before receiving a sensor signal on the other valve. In the illustrated embodiment, precursor 1 pulses 704-1 and 704-2 alternate without overlapping, and precursor 2 pulses 716-1 and 716-2 alternate without overlapping. However, in some embodiments, in order to identify the delay between the command signal and the actual opening or closing of the ALD valve as described above with respect to FIG. 3D, a command signal for opening one of the precursor ALD valves can be sent before receiving an electronic position sensor signal indicating that the previous one in the precursor ALD valve is closed.

[0084] According to an embodiment, precursor 1 pulses 704-1 and 704-2 may have a duration that is a portion of the exposure time of precursor 1 pulses 504-1 and 504-2 as described above with respect to FIG. 5A. For example, the pulse duration may be 20%, 40%, 60%, 80%, or a value within the range defined by any of these values, relative to the exposure time described above with respect to FIG. 5A. Similarly, precursor 2 pulses 716-1 and 716-2 may have a duration that is a portion of the exposure time of precursor 1 pulses 516-1 and 516-2 as described above with respect to FIG. 5A. For example, the pulse duration may be 20%, 40%, 60%, 80%, or a value within the range defined by any of these values, relative to the exposure time described above with respect to FIG. 5A. Without being bound by any theory, such multi-pulse introduction can improve surface saturation by reducing competition between precursor molecules and byproduct molecules. For a given total exposure time, multi-pulse exposure can produce an effective higher dose and / or improved conformability. [application]

[0085] Thin films containing TiN or TiSiN formed using different exposure pressures according to the various embodiments disclosed herein can be used in a variety of applications, particularly where the substrate contains a relatively high aspect ratio structure and / or a non-metallic surface that can benefit from the various advantageous properties of the TiN or TiSiN layers disclosed herein. Example applications include depositing vias, holes, trenches, cavities, or similar structures with an aspect ratio, for example defined as the ratio of depth to top width, exceeding a value within the range defined by 1, 2, 5, 10, 20, 50, 100, 200, or the equivalents thereof.

[0086] Figure 8, illustrated by example, schematically illustrates the application in the context of diffusion barriers in contact structures (e.g., source or drain contacts) formed on heavily doped active semiconductor substrate regions. A portion of a semiconductor device 800 is illustrated, including a substrate 504 on which a dielectric layer 508 is formed, such as an interlayer or intermetallic dielectric (ILD) layer comprising a dielectric material such as oxides or nitrides. To form contacts with various regions of the substrate 504 (including various doped regions, such as source and drain regions), vias or trenches can be formed through the dielectric layer 508. The vias or trenches can expose various non-metallic surfaces, such as an exposed bottom surface including the substrate surface (e.g., a silicon substrate surface) and the dielectric sidewalls of the vias. The bottom and side surfaces of the vias can be conformally coated with TiN or TiSiN layers. Subsequently, the liner vias can be filled with a metal (e.g., W, Al, or Cu) to form contact plugs 516. For example, tungsten can be used, such as WF6, to fill through-holes via CVD.

[0087] The barrier layer 512 formed according to the embodiments can be advantageous for various reasons. Specifically, due to the conformal properties of the barrier layer 512 formed by ALD, the pinch-in tendency during subsequent metal filling processes can be substantially reduced. Additionally, as described above, the barrier layer 512 can effectively impede material transport thereon, for example, impeding diffusion from the substrate 504 of dopants (B, P) and within the contact plug formation process of reactants, etchants, and metals (e.g., F, Cl, W, or Cu). The barrier effect can be enhanced by reducing surface roughness and increasing step coverage. Furthermore, the layer-by-layer growth pattern obtained according to the embodiments can reduce the total contact resistance of the barrier layer 512. Moreover, due to the reduced film roughness, a relatively thin barrier layer 512 can be formed while still achieving its desired barrier function, thereby further reducing contact resistance.

[0088] Other applications of TiN or TiSiN layers formed according to the various embodiments disclosed herein include conductive structures (e.g., embedded electrodes or lines) formed in recessed substrates, electrodes (e.g., DRAM capacitor electrodes or gate electrodes), metallization barriers at higher metal levels (e.g., barriers in vias / trenches of Cu contacts / lines), high aspect ratio vertical rod electrodes or vias for three-dimensional memory and through-silicon vias (TSVs), to name just a few.

[0089] Although the invention has been described herein with reference to specific embodiments, these embodiments are not intended to limit the invention but are illustrative for purposes of explanation. It will be apparent to those skilled in the art that modifications and improvements can be made without departing from the spirit and scope of the invention.

[0090] Such simple modifications and improvements to the various embodiments disclosed herein are within the scope of the disclosed technology, and the specific scope of the disclosed technology will be further defined by the appended claims.

[0091] In the foregoing, it should be understood that any feature of any of the embodiments may be replaced by combination or by any other feature of any of the other embodiments.

[0092] Unless the context explicitly requires otherwise, throughout the specification and scope of the claim, the terms "comprise," "include," and similar terms shall be considered inclusive rather than exclusive or exhaustive; in other words, meaning "including but not limited to." As used herein, the term "coupled" refers to two or more elements that can be directly connected or connected by one or more intermediate elements. Similarly, as used herein, the term "connected" refers to two or more elements that can be directly connected or connected by one or more intermediate elements. Furthermore, when used in this application, the terms "in this document," "above," "below," and similar terms shall refer to the entire application and not any specific part thereof. Where the context permits, the use of singular or plural terms in the above embodiments may also include both singular and plural numbers. When the word "or" refers to a list of two or more items, it encompasses all of the following interpretations of the word: any one of the items in the list, all the items in the list, and any combination of the items in the list.

[0093] Furthermore, unless otherwise specifically stated or understood in the context, the conditional language used herein (such as "can," "may," "can," "may," "for example," "likely," "and the like") is generally intended to convey that certain embodiments include certain features, elements, and / or states that are not included in other embodiments. Therefore, this conditional language is not generally intended to imply that features, elements, and / or states are required in any way for one or more embodiments, or whether such features, elements, and / or states are included in or are to be performed in any particular embodiment.

[0094] While certain embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. In fact, the novel devices, methods, and systems described herein can be embodied in many other forms; furthermore, various omissions, substitutions, and changes can be made to the form of the methods and systems described herein without departing from the spirit of the invention. For example, although features are presented in a given configuration, alternative embodiments may perform similar functionality using different component and / or sensor topologies, and some features may be deleted, moved, added, divided, combined, and / or modified. Each of these features can be implemented in many different ways. Any suitable combination of elements and actions of the various embodiments described above can be combined to provide other embodiments. The various features and processes described above can be implemented independently of each other or can be combined in various ways. All possible combinations and sub-combinations of the features of the invention are intended to be within the scope of the invention.

[0095] 100: Thin Film Deposition System 102: Thin Film Deposition Chamber 106: Precursor Delivery System 108: Nozzle 112: Gas distribution plate 112-1: Cover section 112-2: Cover section 112-3: Cover section 116: Base 120:Substrate 120-1: First precursor source 120-2: First precursor source 124-1: Second precursor source 124-2: Second precursor source 128-1: Flushing gas source 128-2: Flushing gas source 132: Mass Flow Controller 136: manifold 140-1: First precursor atomic layer deposition (ALD) valve 140-2: First precursor ALD valve 144-1: Second Precursor ALD Valve 144-2: Second Precursor ALD Valve 148-1: Flushing Gas ALD Valve 148-2: Flushing Gas ALD Valve 150: Multi-valve block assembly 206: Precursor Delivery System 220-1: Third Precursor ALD Valve 220-2: Third Precursor ALD Valve 220-3: Third Precursor ALD Valve 220-4: Third Precursor ALD Valve 250: Multi-valve block assembly 250-1: Multi-valve block 250-2: Multi-valve block 250-3: Multi-valve block 250-4: Multi-valve block 304-1: First multi-valve block 304-2: Second multi-valve block 308: Input Port 312: Input Port 316: Input Port 320: Input Port 324: Central catheter 328: Outlet conduit 332: Central Exit 350: ALD valve 354: Upper Part 358: Lower Part 362: Coupling section 366: Thermocouple Unit 370-1: Curve 370-2: Curve 370-3: Curve 370-4: Curve 400: Deposition chamber 500A: Exposure Cycle 500B: Exposure Cycle 500C: Exposure Cycle 500D: Exposure Cycle 504:Substrate 504-1: First Precursor Pulse 504-2: First Precursor Pulse 508: Dielectric layer 508-1: First Rapid Rinse (RP) Pulse 508-2: First RP pulse 512: Barrier layer 512-1: Continuous Flushing (CP) 512-2:CP 516: Contact plug 516-1: Second Precursor Pulse 516-2: Second Precursor Pulse 520-1: Second RP pulse 520-2: Second RP pulse 524-1:CP 524-2:CP 600A: Exposure Cycle 600B: Exposure Cycle 600C: Exposure Cycle 600D: Exposure Cycle 604-1: First Precursor Pulse 604-2: First Precursor Pulse 608-1: First RP pulse 608-2: First RP pulse 612-1: Continuous flushing 612-2: Continuous flushing 616-1: Precursor 2 pulse 616-2: Precursor 2 pulse 620-1: Second RP pulse 620-2: Second RP pulse 624-1: Continuous flushing 624-2: Continuous flushing 700A: Exposure Cycle 700B: Exposure Cycle 700C: Exposure Cycle 700D: Exposure Cycle 704-1: Precursor 1 Pulse 704-2: Precursor 1 Pulse 708-1: First RP pulse 708-2: First RP pulse 712-1: Continuous flushing 712-2: Continuous flushing 716-1: Precursor 2 Pulse 716-2: Precursor 2 Pulse 720-1: Second RP pulse 720-2: Second RP pulse 724-1: Continuous flushing 724-2: Continuous flushing 800: Semiconductor Device IN: entrance INERT: Inert Gas Inlet OUT: Export P: Pressure monitoring sensor T: Temperature monitoring sensor

Claims

1. A method of depositing a thin film, the method comprising: alternately exposing a substrate to a plurality of precursors in a thin film deposition chamber in a plurality of cycles, wherein alternately exposing the substrate comprises introducing a first of the precursors into the thin film deposition chamber by independently actuating two or more first atomic layer deposition (ALD) valves, the two or more first ALD valves being connected in parallel to a common gas distribution plate to supply the first of the precursors into the thin film deposition chamber, wherein independently actuating the two or more first ALD valves comprises simultaneously opening the two or more first ALD valves for at least a portion of the time during which the first of the precursors is introduced into the thin film deposition chamber during the same period of the cycles, and wherein the first of the precursors introduced through the two or more first ALD valves is confluent before being introduced through a central opening of the common gas distribution plate.

2. The method of claim 1, wherein the two or more first ALD valves are the final valves of the first of the precursors before they are introduced into the thin film deposition chamber.

3. The method of claim 2, wherein the two or more first ALD valves are vertically positioned above the central region of the substrate.

4. The method of claim 3, wherein the distance between the outlets of the two or more first ALD valves and the main surface of the substrate is in the range of 3 inches to 10 inches.

5. The method of claim 2, wherein each of the two or more first ALD valves is connected to a multi-valve block disposed outside the thin film deposition chamber and configured to act as a hub to receive the first of the precursors and guide the first of the precursors into the thin film deposition chamber via an internal conduit defined in the multi-valve block.

6. The method of claim 5, wherein the internal conduits include a central conduit extending in a vertical direction, the central conduit passing through the main surface of the substrate and connected to the thin film deposition chamber to feed the first of the precursors into the thin film deposition chamber.

7. The method of claim 6, wherein the central conduit is the final conduit through which the first of the precursors passes before being introduced into the thin film deposition chamber.

8. The method of claim 1, wherein the deposition of the thin film comprises deposition by thermal ALD without the aid of plasma.

9. The method of claim 8, wherein alternating exposure of the substrate comprises a first exposure of the precursors comprising one of a metal precursor and an oxide precursor, followed by the exposure of the precursors comprising the other of the metal precursor and the oxide precursor.

10. The method of claim 9, wherein actuating the two or more first ALD valves includes substantially simultaneously opening the two or more first ALD valves during the introduction of the first of the precursors into the thin film deposition chamber.

11. The method of claim 9, wherein introducing the first of the precursors into the thin film deposition chamber includes introducing it via the two or more first ALD valves at a combined flow rate, such that the exposure time to reach substantial saturation at the surface of the substrate is reduced by 20% to 80%, wherein substantial saturation corresponds to a condition in which increasing the exposure time does not substantially increase the growth rate.

12. The method of claim 9, wherein introducing the first of the precursors into the thin film deposition chamber includes introducing it via the two or more ALD valves at a combined flow rate such that the surface of the substrate is exposed to the first of the precursors for an exposure time ranging from 0.1 seconds to 1.0 seconds.

13. The method of claim 9, wherein alternating exposure of the substrate comprises introducing the second of the precursors into the thin film deposition chamber by independently actuating two or more second ALD valves, the two or more second ALD valves being connected in parallel to the common gas distribution plate to supply the second of the precursors into the thin film deposition chamber.

14. The method of claim 9, wherein each of the two or more first ALD valves has a response time ranging from 5 ms to 30 ms between the end of the command signal and the completion of the opening or closing of the diaphragm of the two or more first ALD valves.

15. The method of claim 9, wherein each of the two or more first ALD valves has a valve flow coefficient (Cv) of more than 0.

25.

16. The method of claim 9, further comprising heating the two or more first ALD valves to a valve temperature exceeding 80°C before and during actuation of the two or more first ALD valves.

17. The method of claim 9, wherein introducing the first of the precursors into the thin film deposition chamber comprises allowing an inert gas to continuously flow into the thin film deposition chamber via each of the two or more first ALD valves, while introducing the first of the precursors into the thin film deposition chamber.

18. The method of claim 9, further comprising introducing flushing gas into the thin film deposition chamber by actuating two or more flushing ALD valves connected in parallel to the common gas distribution plate after each of the precursors has been introduced.

19. The method of claim 9, wherein the thin film comprises a TiN thin film or a TiSiN thin film.

20. The method of claim 9, wherein the plurality of precursors includes one or more of Ti precursors, Si precursors and N precursors.

21. The method of claim 9, wherein the thin film deposition chamber comprises a plurality of processing stations, each configured to deposit the thin film.

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