Patent Application
20190267249
The present invention relates to the field of semiconductor manufacturing and semiconductor devices, and more particularly, to atomic layer etching (ALE) of a substrate using a boron-containing gas and hydrogen fluoride (HF) gas.
As device feature size continues to scale it is becoming a significant challenge to accurately control etching of fine features. For highly scaled nodes 10 nm and below, devices require atomic scaled fidelity or very tight process variability. There is significant impact on device performance due to variability. In this regards, self-limiting and atomic scale processing methods such as ALE are becoming a necessity.
A method is provided for ALE of a substrate. According to one embodiment, the method includes providing a substrate, and exposing the substrate to HF gas and a boron-containing gas to etch the substrate.
According to another embodiment, the method includes providing a substrate containing a metal oxide film, exposing the substrate to HF gas to form a fluorinated surface layer on the metal oxide film, and exposing the substrate to a boron-containing gas to remove the fluorinated surface layer from the metal oxide film. The exposures may be repeated at least once to further etch the metal oxide film.
According to yet another embodiment, the method includes providing a substrate containing a metal oxide film having a first fluorinated surface layer, exposing the substrate to a first boron-containing gas to remove the first fluorinated surface layer from the metal oxide film, exposing the substrate to HF gas to form a second fluorinated surface layer on the metal oxide film, and exposing the substrate to a second boron-containing gas to remove the second fluorinated surface layer from the metal oxide film. The exposures to the HF gas and the second boron-containing gas may be repeated at least once to further etch the metal oxide film.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Developing advanced technology for advanced semiconductor technology nodes presents an unprecedented challenge for manufacturers of semiconductor devices, where these devices will require atomic-scale manufacturing control of etch variability. ALE is viewed by the semiconductor industry as an alternative to conventional continuous etching. ALE is a substrate processing technique that removes thin layers of material using sequential self-limiting reactions and is considered one of the most promising techniques for achieving the required control of etch variability necessary in the atomic-scale era.
ALE is often defined as a film etching technique that uses sequential self-limiting reactions. The concept is analogous to atomic layer deposition (ALD), except that removal occurs in place of a second adsorption step, resulting in layer-by-layer material removal instead of addition. The simplest ALE implementation consists of two sequential steps: surface modification (1) and removal (2). Surface modification forms a thin reactive surface layer with a well-defined thickness that is subsequently more easily removed than the unmodified material. The thin reactive surface layer is characterized by a sharp gradient in chemical composition and/or physical structure of the outermost layer of a material. The removal step takes away at least a portion of the thin reactive surface layer while keeping the underlying substrate intact, thus “resetting” the surface to a suitable state for the next etching cycle. The total amount of material removed is determined by the number of repeated cycles.
Embodiments of the invention provide a method for manufacturing of semiconductor devices, and more particularly, to ALE using HF gas and a boron-containing gas.
The first and second boron-containing gases 506 and 512 can contain a boron hydride, a boron halide, a boron amide, an organo boride, or a combination thereof. The first and second boron-containing gases 506 and 512 may independently be selected from the group consisting of BH3, BCl3, B(CH3)3, and B(N(CH3)2)3. As shown by process arrow 412, the exposures 404-410 may be repeated at least once to further etch the metal oxide film 502.
A plurality of embodiments for atomic layer etching using a boron-containing gas and HF gas have been described. The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. This description and the claims following include terms that are used for descriptive purposes only and are not to be construed as limiting. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above teaching. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
This application is a continuation of co-pending U.S. patent application Ser. No. 15/671,404 filed on Aug. 8, 2017, the entire contents of which are herein incorporated by reference. This application is related to and claims priority to U.S. Provisional Patent Application Ser. No. 62/373,232 filed on Aug. 10, 2016, the entire contents of which are herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15671404 | Aug 2017 | US |
| Child | 16405462 | US |
