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US-12618134-B2 - Normal pulse profile modification in a film deposition process

US12618134B2US 12618134 B2US12618134 B2US 12618134B2US-12618134-B2

Abstract

There is disclosed apparatus and processes for the uniform controlled growth of materials on a substrate which direct a plurality of pulsed flows of a precursor into a reaction space of a reactor to deposit the thin film on the substrate. Each pulsed flow is a combination of a first pulsed subflow and a second pulsed subflow, wherein a pulse profile of the second pulsed subflow overlaps at least a portion of a latter half of a pulse profile of the first pulsed subflow.

Inventors

  • Chiyu Zhu

Assignees

  • ASM IP HOLDING B.V.

Dates

Publication Date
20260505
Application Date
20220823

Claims (13)

  1. 1 . A system for depositing a thin film on a substrate comprising: a reactor defining a reaction space therein; a first path and a second path in fluid communication with the reactor and the reaction space, wherein the first path and the second path intersect prior to the reactor; a single precursor source comprising a precursor, the single precursor source in fluid communication with the first path and the second path for delivering a precursor there through; and a controller configured to control of a flow of the precursor through each of the first and second paths to direct a plurality of pulsed flows of the precursor to the reaction space, wherein, in the reaction space, each pulsed flow comprises a combination of a first pulsed subflow and a second pulsed subflow of the same precursor flowing through the first path and the second path, respectively; wherein a pulse profile of the second pulsed subflow overlaps in time with at least a portion of a latter half of a pulse profile of the first pulsed subflow to form a combined pulsed subflow having a non-uniform pulse profile, and wherein a maximum in the pulse profile of the second pulsed subflow is greater than a maximum in the pulse profile of the first pulsed subflow.
  2. 2 . The system of claim 1 , wherein the controller is configured to deliver the second pulsed subflow to the reaction space at a greater mass flow rate than that of the first pulsed subflow.
  3. 3 . The system of claim 1 , wherein the controller is configured to provide the second pulsed subflow within a shorter period of time relative to the first pulsed subflow.
  4. 4 . The system of claim 1 , wherein the controller is configured to provide a greater concentration of the precursor in the second pulsed subflow per unit time than in the first pulsed subflow.
  5. 5 . The system of claim 1 , wherein a conductance of the first path and the second path are different.
  6. 6 . The system of claim 5 , wherein the difference in conductance between the first path and the second path comprises a difference in path length, a degree of flow restriction, or a cross sectional length between the first path and the second path.
  7. 7 . The system of claim 1 , wherein the first path and the second path are in fluid communication with a common reactant source for the first pulsed subflow and the second pulsed subflow, and wherein the first path and the second path intersect prior to the reaction space to deliver each pulsed flow to the reaction space.
  8. 8 . The system of claim 1 , wherein a time difference between the maximum in the pulse profile of the first pulsed subflow and the maximum in the pulse profile of the second pulsed subflow is from 10 ms to 1000 ms.
  9. 9 . The system of claim 1 , wherein the maximum in the pulse profile of the second pulsed subflow is at least 10% greater than the maximum of the precursor in the pulse profile of the first pulsed subflow.
  10. 10 . The system of claim 1 , further comprising a purge gas source comprising a purge gas in fluid communication with the reactor, wherein the controller is configured to deliver purge gas from the purge gas source to the reaction space between selected ones of the plurality of pulsed flows.
  11. 11 . A system for depositing a film on a substrate comprising: a reactor defining a reaction space therein; a first path and a second path in fluid communication with the reaction space; a precursor source comprising a precursor, the precursor source in fluid communication with the first path and the second path; and a controller configured to control of a flow of the precursor through the first and second paths to direct a plurality of pulsed flows of the precursor to the reaction space, wherein, in the reaction space, each pulsed flow comprises a combination of a first pulsed subflow and a second pulsed subflow of the precursor flowing through the first path and the second path, respectively; wherein a pulse profile of the second pulsed subflow overlaps in time with at least a portion of a latter half of a pulse profile of the first pulsed subflow, and wherein a duration of each of the first pulsed subflow and the second pulsed subflow is from 10 to 10000 ms.
  12. 12 . A system for depositing a film on a substrate comprising: a reactor defining a reaction space therein; a first path and a second path in fluid communication with the reaction space; a precursor source comprising a precursor, the precursor source in fluid communication with the first path and the second path; and a controller configured to control of a flow of the precursor through each of the first and second paths to direct a plurality of pulsed flows of the precursor to the reaction space, wherein, in the reaction space, each pulsed flow comprises a combination of a first pulsed subflow and a second pulsed subflow of the precursor flowing through the first path and the second path, respectively; wherein a pulse profile of the second pulsed subflow overlaps in time with at least a portion of a latter half of a pulse profile of the first pulsed subflow, and wherein the precursor is a transition metal-containing compound; a silicon-containing compound; an organometallic compound; plasma, excited species, or radicals comprising nitrogen, oxygen or hydrogen; ammonia; O 2 ; or O 3 .
  13. 13 . The system of claim 12 , wherein the precursor is a transition metal-containing compound; a silicon-containing compound; or an organometallic compound.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional application of U.S. patent application Ser. No. 17/078,119, filed Oct. 23, 2020, which claims priority to and the benefit of U.S. Provisional Patent Application No. 62/925,787, filed Oct. 25, 2019, each of which is incorporated by reference herein in its entirety. FIELD The present invention relates to the controlled growth of materials on a substrate, and in particular to apparatus and processes for the uniform and rapid controlled growth of materials on a substrate during a film deposition process. BACKGROUND Thin film deposition is used to build materials by growing materials on a substrate. The resulting substrates have widespread usage in microelectronics, as well as in other fields. Two well-known thin film deposition techniques are atomic layer deposition (ALD) and Chemical Vapor Deposition (CVD). In each technique, one or more reactants (precursors), typically in the form of gases, are fed into a reactor, which repeatedly grow a desired film or layer on the substrate. During normal operation of ALD, the precursor is pulsed into the reactor, and each precursor pulse reacts with a finite number of reactive sites on the available surface. Once all the reactive sites are consumed, growth stops. The remaining precursor molecules in the reactor are flushed away with a purge gas and then the next precursor is delivered to the reactor. By alternatingly introducing a first and a second precursor, a thin film is deposited on the substrate. When describing an ALD process, one refers to both dose times (the time a surface is exposed to a precursor) and purge times (the time left between doses for the precursor to evacuate the reactor) for each precursor. The dose-purge-dose-purge sequence of a binary ALD process constitutes an ALD cycle. Within an ALD process, it is known that the pulse profile of a precursor has an influence on the resulting layer. Pulse profile refers to the amount of reactant delivered per unit time for a duration of the pulse. The amount of reactant delivered within each pulse may be a function of flow velocity or/and of concentration; that is, the amount of precursor may be dependent on the volumetric flow rate and/or a concentration of the precursor in the carrier gas (if a carrier gas is used). In known methods, the flow rate of precursor being constant, the pulse profile typically shows a high concentration spike at the leading edge of the pulse and the concentration then tails off. This leads to non-uniformity in the film of the substrate, namely the layer generated by each pulse tends to be thicker at a leading edge and thinner at a trailing edge thereof. Accordingly, processes which provide for a more uniform film deposition thickness in thin film processes, such as ALD, are desired. SUMMARY In accordance with an aspect of the present invention, the present inventors have developed apparatus and processes for the uniform and rapid controlled growth of thin films on a substrate. In one aspect, there is provided method of depositing a thin film on a substrate comprising: directing a plurality of pulsed flows of a precursor into a reaction space of a reactor to deposit the thin film on the substrate, each pulsed flow comprising a combination of a first pulse subflow and a second pulse subflow, wherein a pulse profile of the second pulse subflow overlaps at least a portion of a latter half of a pulse profile of the first pulse subflow. By providing a more uniform distribution throughout the pulse profile and a greater amount of precursor toward a trailing end of the pulsed flow relative to known methods, a more uniform thin film deposit is provided. In accordance with another aspect, there is provided a system for depositing a thin film on a substrate comprising: a reactor defining a reaction space therein;a first path and a second path in fluid communication with the reactor and the reaction space, wherein the first path and the second path intersect prior to the reactor;at least one precursor source in fluid communication with the first path and the second path for delivering a precursor there through;a controller configured to control of a flow of the precursor through each of the first and second paths to direct a plurality of pulsed flows of the precursor to the reaction space, wherein each pulsed flow comprises a combination of a first pulsed subflow and a second pulsed subflow flowing through the first path and the second path, respectively;wherein a pulse profile of the second pulsed subflow overlaps at least a portion of a latter half of a pulse profile of the first pulsed subflow. BRIEF DESCRIPTION OF THE DRAWINGS While the specification concludes with claims particularly pointing out and distinctly claiming what are regarded as embodiments of the invention, the advantages of embodiments of the disclosure may be more readily ascertained from the description of certain examples of the embodiments of the dis