Patent Application
20230366089
The present disclosure relates generally to a showerhead for substrate processing applications, and more particularly to a faceless showerhead for aluminum oxide (AlOx) processes.
Conventional showerheads typically include a plenum connected to multiple holes in a faceplate to distribute precursor gases (precursors) into a processing chamber to achieve a desired on-wafer uniformity or feature creation on a substrate, for example. The existence of a plenum and thousands of holes can significantly increase the cost of showerhead. In one problematic aspect, in view of high deposition rates in AlOx processes, AlOx process hardware can become prone to flaking and particle generation. Other such issues may not be tied to deposition rates. For example, there is a difficulty in using conventional dry etch methods of in-situ cleaning of components such as a showerhead. Without in-situ cleaning, a film will build up over time and flake. Addressing this situation may require multiple wet cleans and part replacement, thereby increasing inventory, wastage and labor costs at a manufacturing site.
The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
In some examples, a faceless showerhead comprises a body including a backing plate, the body devoid of a faceplate or plenum; a gas supply stem to admit gas into the showerhead; and a baffle supported adjacent the backing plate or the gas supply stem.
In some examples, the faceless showerhead further comprises at least one support element for supporting the baffle in a baffle cavity in the backing plate or the gas supply stem.
In some examples, a diameter of the backing plate is in a range 12 mm-105 mm. In some examples, a diameter of the baffle is in a range 2.5 mm-13 mm.
In some examples, a thickness of the baffle is in a range 0.5 mm-3 mm. In some examples, a separation distance between the baffle and the backing plate is in a range 0.1 mm-6 mm. In some examples, a separation distance between the baffle and the gas supply stem is in a range 0.5 mm-6 mm.
In some examples, the baffle includes an arrangement of one or more through-holes, and wherein a diameter of a through-hole is in a range 0.2 mm-10 mm. In some examples, a diameter of an inner or outer circular pattern of the through-hole arrangement is in a range 2 mm-100 mm. In some examples, a diameter of the support element is in a range 1 mm-10 mm, and a length of the support element is in a range 0.5 mm-6 mm.
Some embodiments are illustrated by way of example and not limitation in the views of the accompanying drawings:
The description that follows includes systems, methods, techniques, instruction sequences, and computing machine program products that embody illustrative embodiments of the present disclosure. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of example embodiments. It will be evident, however, to one skilled in the art that the present disclosure may be practiced without these specific details.
A portion of the disclosure of this patent document may contain material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. The following notice applies to any data as described below and in the drawings that form a part of this document: Copyright Lam Research Corporation, 2020, All Rights Reserved.
Conventional precursor delivery systems employ a plenum of one sort or another. The existence of a plenum can lead to the disadvantages described above. Deposition can become trapped in an inaccessible plenum or inside thousands of tiny holes. It will be appreciated that cleaning the inside of a conventional plenum or holes can be difficult and costly.
Thus, in one aspect, this disclosure seeks to provide a low-cost version of a showerhead for substrate processing, for example AlOx-based processes. Some present examples eliminate a plenum requirement. Process optimization can be addressed through baffle design and chemistry types, as described further below. Some examples reduce the cost of the showerhead and maintenance cost. Some embodiments employ a configuration that significantly reduces hardware costs while meeting desired functional specifications, for example in AlOx processes.
With reference now to
The skilled artisan will also recognize that other types of ALD processing techniques, such as AlOx processes, are known (e.g., thermal-based ALD operations) and may incorporate a non-plasma-based processing chamber. An ALD tool is a specialized type of CVD processing system in which ALD reactions occur between two or more chemical species. The two or more chemical species are referred to as precursor gases and are used to form a thin film deposition of a material on a substrate, such as a silicon wafer as used in the semiconductor industry. The precursor gases are sequentially introduced into an ALD processing chamber and react with a surface of the substrate to form a deposition layer. Generally, the substrate repeatedly interacts with the precursors to deposit slowly an increasingly thick layer of one or more material films on the substrate. In certain applications, multiple precursor gases may be used to form various types of film or films during a substrate manufacturing process.
In operation, the substrate 106 is loaded through a loading port 110 onto the substrate-support assembly 108. A gas line 114 can supply one or more process gases (e.g., precursor gases) to the showerhead 104. In turn, the showerhead 104 delivers the one or more process gases into the plasma-based processing chamber 102. A gas source 112 (e.g., one or more precursor gas ampules) to supply the one or more process gases is coupled to the gas line 114. In some examples, an RF (radio frequency) power source 116 is coupled to the showerhead 104. In other examples, a power source is coupled to the substrate-support assembly 108 or ESC.
Prior to entry into the showerhead 104 and downstream of the gas line 114, a point-of-use (POU) and manifold combination (not shown) controls entry of the one or more process gases into the plasma-based processing chamber 102. Typically, and with reference to a conventional showerhead 202 illustrated in
In operation, the plasma-based processing chamber 102 is evacuated by a vacuum pump 118. RF power is capacitively coupled between the showerhead 104 and a lower electrode 120 contained within or on the substrate-support assembly 108. The substrate-support assembly 108 is typically supplied with two or more RF frequencies. For example, in various embodiments, the RF frequencies may be selected from at least one frequency at about 1 MHz, 2 MHz, 13.56 MHz, 27 MHz, 60 MHz, and other frequencies as desired. A coil designed to block or partially block a particular RF frequency can be designed as needed. Therefore, particular frequencies discussed herein are provided merely for ease in understanding. The RF power is used to energize the one or more process gases into a plasma in the space between the substrate 106 and the showerhead 104. The plasma can assist in depositing various layers (not shown) on the substrate 106. In other applications, the plasma can be used to etch device features into the various layers on the substrate 106. RF power is coupled through at least the substrate-support assembly 108. The substrate-support assembly 108 may have heaters incorporated therein. The detailed design of the processing chamber 102 may vary and it may, or may not, be plasma-based in use of present example showerheads.
A phrase that may be used by skilled artisans when describing process optimization in the substrate-processing or semiconductor arts is the “adjustment of knobs”. This term relates to process factors or chamber parameters that can be fine-tuned to bring about a desired process or outcome, for example the creation of certain specified nano-sized features on a wafer, film thickness, or other substrate characteristics, for example. Various desired outcomes or results can be obtained or fine-tuned by “adjusting the knobs”.
Some examples of a faceless showerhead 302 enable such fine-tuning in various ways. Fine-tuning factors enabled by a faceless showerhead 302 may include, for example, a general configuration, position, or dimension of the faceless showerhead 302 per se or with respect to a substrate 106; a diameter, thickness, or other dimension of the baffle 306; an arrangement or configuration of holes in the baffle 306; a diameter or shape of holes in the baffle 306; a presence or absence of holes in the baffle 306; a separation distance between the baffle 306 and the gas supply stem 308; a separation distance between the baffle 306 and the backing plate 304; and a dimension or placement of a support element 310. Other fine-tuning factors are possible. For example, the baffle may be heated or cooled. The backing plate may be heated or cooled. In some examples, the backing plate assumes a particular configuration, such as including a convex or concave portion. A baffle 306 may be removable, or quickly replaceable by a baffle of an alternate configuration. Some specific examples of faceless showerheads are now described.
The faceless showerhead 402 illustrated in
In
The length, placement, or configuration of the support elements 410, 510, and 610 can be selected to create inter-relationships or functionality between and among the components of the faceless showerheads 402, 502, and 602 as desired. A given support element 410, 510 and 610 may be removed or quickly replaced by another support element 410, 510 and 610 of an alternate length or configuration. With reference to
With reference to the accompanying figures, in some examples a diameter of the backing plate is in the range 12 mm-105 mm or 2.5 mm-13 mm. In some examples, a diameter of the baffle is in the range 12 mm-105 mm or 2.5 mm-13 mm. In the illustrated examples shown in the drawings, the diameter of the baffle is smaller than the diameter of the backing plate, for example in the nested-baffle configuration of
Other shapes besides circular are possible for the baffle and the backing plate. For example, the baffle or backing plate could assume or include one or more different shapes, for example a triangular, hexagonal, crescent or amorphous shape. In some examples, a specific shape of the baffle or backing plate enables a further knob for tuning a given process.
In some examples, holes or posts are provided at or in the center of the baffle or the gas supply stem. In some examples, the gas supply stem includes a specific inner or outer diameter to enable a further process knob. In some examples, an inner diameter of a gas supply stem is in the range 2 mm to 80 mm. In some examples, an outer diameter of a gas supply stem is in the range 25 mm to 150 mm. In some examples, the inner or outer diameter of a stem may or may not be cylindrical, or circular in cylindrical outline.
Some present examples include methods. With reference to
In some examples, the faceless showerhead includes any one or more of the features described elsewhere herein. In some examples, the method 800 further comprises striking a plasma in the substrate processing chamber, or not striking a plasma in the substrate processing chamber.
Although examples have been described with reference to specific example embodiments or methods, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader scope of the embodiments. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. The accompanying drawings that form a part hereof, show by way of illustration, and not of limitation, specific embodiments in which the subject matter may be practiced. The embodiments illustrated are described in sufficient detail to enable those skilled in the art to practice the teachings disclosed herein. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. This detailed description, therefore, is not to be taken in a limiting sense, and the scope of various embodiments is defined only by the appended claims, along with the full range of equivalents to which such claims are entitled.
Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.
This application claims the benefit of priority to U.S. patent application Ser. No. 63/089,969, filed on Oct. 9, 2020, which is incorporated by reference herein in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/054152 | 10/8/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63089969 | Oct 2020 | US |
