Patents by Inventor ALOK RANJAN

ALOK RANJAN has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20190393048
    Abstract: Embodiments provide area-selective etching of silicon nitride for the manufacture of microelectronic workpieces through sequential exposure of silicon nitride layers to hydrogen ions/radicals followed by fluorine ions/radicals using beam delivery techniques such as ion beam and/or neutral beam techniques. The area-selective etch processes are anisotropic when hydrogen ions are used and are isotropic when hydrogen radicals are used. Further, sputtering of material onto a substrate for a microelectronic workpiece is not required for the disclosed embodiments. Further, by using ion beam and/or neutral beam techniques, area-selective etching of silicon nitride is achieved as opposed to the large-area etching provided by prior plasma processing techniques. For certain embodiments, the ion/neutral beam techniques described herein are used to fabricate silicon nitride hard masks without requiring the use of any mask.
    Type: Application
    Filed: June 20, 2019
    Publication date: December 26, 2019
    Inventors: Sonam D. Sherpa, Alok Ranjan
  • Patent number: 10515814
    Abstract: A method of etching is described. The method includes providing a substrate having a first material containing silicon nitride and a second material that is different from the first material, forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing N, F, O, and optionally a noble element, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second material.
    Type: Grant
    Filed: February 28, 2019
    Date of Patent: December 24, 2019
    Assignee: TOKYO ELECTRON LIMITED
    Inventors: Sonam D. Sherpa, Alok Ranjan
  • Patent number: 10490404
    Abstract: Systems and methods for in situ hard mask removal are described. In an embodiment, a method includes receiving a semiconductor workpiece comprising a substrate, an intermediary layer, a hard mask layer, and a photoresist layer in an etch chamber. The method may also include etching the hard mask layer to open a region left exposed by the photoresist layer. Additionally, such an embodiment may include etching the intermediary layer in a region left exposed by the hard mask layer. The method may also include removing the hard mask layer. In such embodiments, etching the hard mask layer, etching the intermediary layer, and removing the hard mask layer are performed in the etch chamber, and without the wafer being removed from the etch chamber.
    Type: Grant
    Filed: September 19, 2017
    Date of Patent: November 26, 2019
    Assignee: Tokyo Electron Limited
    Inventors: Christopher Talone, Andrew Nolan, Mingmei Wang, Alok Ranjan
  • Patent number: 10483127
    Abstract: A plasma processing system and methods for high precision etching of microelectronic substrates. The system may include a combination of microwave and radio frequency (RF) power sources that may generate plasma conditions to remove monolayer(s). The system may generation a first plasma to form a thin adsorption layer on the surface of the microelectronic substrate. The adsorbed layer may be removed when the system transition to a second plasma. The differences between the first and second plasma may be include the ion energy proximate to the substrate. For example, the first plasma may have an ion energy of less than 20 eV and the second plasma may have an ion energy greater than 20 eV.
    Type: Grant
    Filed: November 26, 2018
    Date of Patent: November 19, 2019
    Assignee: Tokyo Electron Limited
    Inventors: Mingmei Wang, Alok Ranjan, Peter L. G. Ventzek
  • Publication number: 20190348296
    Abstract: In one exemplary embodiment, described herein is an ALE process for etching an oxide. In one embodiment, the oxide is silicon oxide. The ALE modification step includes the use of a carbon tetrafluoride (CF4) based plasma. This modification step preferentially removes oxygen from the surface of the silicon oxide, providing a silicon rich surface. The ALE removal step includes the use of a hydrogen (H2) based plasma. This removal step removes the silicon enriched monolayer formed in the modification step. The silicon oxide etch ALE process utilizing CF4 and H2 steps may be utilized in a wide range of substrate process steps. For example, the ALE process may be utilized for, but is not limited to, self-aligned contact etch steps, silicon fin reveal steps, oxide mandrel pull steps, oxide spacer trim, and oxide liner etch.
    Type: Application
    Filed: May 2, 2019
    Publication date: November 14, 2019
    Inventors: Sonam D. Sherpa, Alok Ranjan
  • Publication number: 20190348295
    Abstract: Embodiments provide isotropic and selective etching of silicon nitride layers for the manufacture of microelectronic workpieces through sequential exposure of silicon nitride layers to plasma including hydrogen radicals and plasma including fluorine radicals. For example, the sequential application of plasma etch steps can use: (1) a first plasma gas including hydrogen (H2) and argon (Ar), and (2) a second plasma gas including nitrogen trifluoride (NF3), oxygen (O2), and Ar. These plasma gases are ignited within a processing region or chamber under sufficient pressure to generate the hydrogen radicals and the fluorine radicals. Other plasma gas chemistries can also be used under sufficient pressures to generate alternating application of hydrogen radicals and fluorine radicals.
    Type: Application
    Filed: April 9, 2019
    Publication date: November 14, 2019
    Inventors: Sonam D. Sherpa, Alok Ranjan
  • Publication number: 20190318913
    Abstract: Multiple harmonic frequency components are used for plasma excitation in a plasma process. Relative amplitude and/or phase shift between the different frequency components is controlled so as to provide desired ion energy plasma properties. The relative amplitude and/or phase shift may be controlled without direct and/or manual ion energy measurements. Rather, the ion energy within the plasma may be dynamically controlled by monitoring one or more electrical characteristics within the plasma apparatus, such as for example, impedance levels, electrical signals in the radio frequency (RF) generator, electrical signals in a the matching networks, and electrical signals in other circuits of the plasma processing apparatus. The monitoring and control of the ion energy may be accomplished dynamically during the plasma process so as to maintain a desired ion energy distribution.
    Type: Application
    Filed: April 8, 2019
    Publication date: October 17, 2019
    Inventors: Yusuke Yoshida, Sergey Voronin, Alok Ranjan, David J. Coumou, Scott E. White
  • Publication number: 20190318916
    Abstract: Plasma ion energy distribution for ions having different masses is controlled by controlling the relationship between a base RF frequency and a harmonic RF frequency. By the controlling the RF power frequencies, characteristics of the plasma process may be changed based on ion mass. The ions that dominate etching may be selectively based upon whether an ion is lighter or heavier than other ions. Similarly, atomic layer etch processes may be controlled such that the process may be switched between a layer modification step and a layer etch step though adjustment of the RF frequencies. Such switching is capable of being performed within the same gas phase of the plasma process. The control of the RF power includes controlling the phase difference and/or amplitude ratios between a base RF frequency and a harmonic frequency based upon the detection of one or more electrical characteristics within the plasma apparatus.
    Type: Application
    Filed: April 8, 2019
    Publication date: October 17, 2019
    Inventors: Yusuke Yoshida, Sergey Voronin, Alok Ranjan, David J. Coumou, Scott E. White
  • Patent number: 10446405
    Abstract: A method of preparing a self-aligned block (SAB) structure is described. The method includes providing a substrate having raised features defined by a first material containing silicon nitride and a second material containing silicon oxide formed on side walls of the first material, and a third material containing an organic material covering some of the raised features and exposing some raised features according to a block pattern formed in the third material. The method further includes forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture.
    Type: Grant
    Filed: February 23, 2018
    Date of Patent: October 15, 2019
    Assignee: TOKYO ELECTRON LIMITED
    Inventors: Sonam D. Sherpa, Alok Ranjan
  • Patent number: 10446407
    Abstract: Embodiments of the invention describe substrate processing methods using non-polymerizing chemistry to preferentially etch silicon nitride relative to other materials found in semiconductor manufacturing. According to one embodiment, a processing method includes providing in a plasma processing chamber a substrate containing a first material containing silicon nitride and a second material that is different from the first material, forming a plasma-excited process gas containing SF6, and exposing the substrate to the plasma-excited process gas to preferentially etch the first material relative to the second material. In one example, the process gas can contain or consist of SF6 and Ar. In another example, the second material is selected from the group consisting of Si and SiO2.
    Type: Grant
    Filed: January 18, 2018
    Date of Patent: October 15, 2019
    Assignee: Tokyo Electron Limited
    Inventors: Sonam D. Sherpa, Alok Ranjan
  • Publication number: 20190304798
    Abstract: Methods and systems for cyclic etching of a patterned layer are described. In an embodiment, a method includes receiving a substrate comprising an underlying layer, a mask layer that exposes portions of an intermediate layer that is disposed between the underlying layer and the mask layer. An embodiment may also include forming a first layer on the mask layer and a second layer on the exposed portions of the intermediate layer, the first layer and the second layer being concurrently formed. Additionally, the method may include removing, concurrently, the first layer and the second layer from the substrate. In such embodiments, the method may include alternating between the forming and the removing until portions of the underlying layer are exposed.
    Type: Application
    Filed: June 19, 2019
    Publication date: October 3, 2019
    Applicant: Tokyo Electron Limited
    Inventors: Alok Ranjan, Vinayak Rastogi
  • Publication number: 20190304750
    Abstract: Methods and systems for treating a substrate are described. In an embodiment, a method may include receiving a microelectronic substrate in a plasma processing chamber. A method may also include receiving process gas in the plasma processing chamber. Additionally, a method may include applying energy to the process gas with a first energy source and applying energy to the process gas with a second energy source. The method may further include selectively adjusting at least one of the first energy source and the second energy source between a first state and a second state.
    Type: Application
    Filed: March 29, 2018
    Publication date: October 3, 2019
    Inventors: Sergey Voronin, Christopher Talone, Alok Ranjan
  • Patent number: 10431470
    Abstract: A method of etching is described. The method includes providing a substrate having a first material containing silicon nitride and a second material that is different from the first material, forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing S and F, and optionally a noble element, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second material.
    Type: Grant
    Filed: February 23, 2018
    Date of Patent: October 1, 2019
    Assignee: TOKYO ELECTRON LIMITED
    Inventors: Sonam D. Sherpa, Alok Ranjan
  • Publication number: 20190259623
    Abstract: Sidewall etching of substrate features may be achieved by employing an etch stop layer formed over the features. The etch stop layer is thinner on sidewalls of the features as compared to the bottom of the features. The lateral etching of the features is achieved by use of an over etch which breaks through the etch stop layer on the sidewalls of the features but does not break through the etch stop layer formed at the bottom of the features. The use of the etch stop layer allows for lateral etching while preventing unwanted vertical etching. The lateral etching may be desirable for use in a number of structures, including but not limited to 3D structures. The lateral etching may also be used to provide vertical sidewalls by reducing the sidewall taper angle.
    Type: Application
    Filed: February 15, 2019
    Publication date: August 22, 2019
    Inventors: Shyam Sridhar, Nayoung Bae, Sergey Voronin, Alok Ranjan
  • Publication number: 20190252197
    Abstract: A method of etching is described. The method includes providing a substrate having a first material containing silicon nitride and a second material that is different from the first material, forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing N, F, O, and optionally a noble element, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second material.
    Type: Application
    Filed: February 28, 2019
    Publication date: August 15, 2019
    Applicant: TOKYO ELECTRON LIMITED
    Inventors: Sonam D. SHERPA, Alok RANJAN
  • Patent number: 10381235
    Abstract: Embodiments of the invention provide a substrate processing method for selective SiN etching relative to other layers used in semiconductor manufacturing. According to one embodiment, the substrate processing method includes providing in a plasma processing chamber a substrate containing a first material containing silicon nitride and a second material that is different from the first material, forming a plasma-excited process gas containing NF3 and O2, and exposing the substrate to the plasma-excited process gas to selectively etch the first material relative to the second material. According to one embodiment, the second material may be selected from the group consisting of Si, SiO2, and a combination thereof.
    Type: Grant
    Filed: May 26, 2017
    Date of Patent: August 13, 2019
    Assignee: Tokyo Electron Limited
    Inventors: Alok Ranjan, Vinayak Rastogi, Sonam D. Sherpa
  • Patent number: 10373828
    Abstract: According to one embodiment, a substrate processing method includes providing a substrate containing Si raised features, depositing a conformal film on the Si raised features, and performing a spacer etch process that removes horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film to form sidewall spacers on the Si raised features, the performing including a) exposing the substrate to a plasma-excited first process gas consisting of H2 gas and optionally an inert gas, and b) exposing the substrate to a plasma-excited second process gas containing i) NF3, O2, H2, and Ar, ii) NF3, O2, and H2, iii) NF3 and O2, iv) NF3, O2, and Ar, v) NF3 and H2, or vi) NF3, H2, and Ar. The method further includes removing the Si raised features while maintaining the sidewall spacers on the substrate. The removing may be performed using steps a) and b).
    Type: Grant
    Filed: May 26, 2017
    Date of Patent: August 6, 2019
    Assignee: Tokyo Electron Limited
    Inventors: Alok Ranjan, Sonam D. Sherpa
  • Patent number: 10366902
    Abstract: Methods and systems for cyclic etching of a patterned layer are described. In an embodiment, a method includes receiving a substrate comprising an underlying layer, a mask layer that exposes portions of an intermediate layer that is disposed between the underlying layer and the mask layer. An embodiment may also include forming a first layer on the mask layer and a second layer on the exposed portions of the intermediate layer, the first layer and the second layer being concurrently formed. Additionally, the method may include removing, concurrently, the first layer and the second layer from the substrate. In such embodiments, the method may include alternating between the forming and the removing until portions of the underlying layer are exposed.
    Type: Grant
    Filed: February 22, 2017
    Date of Patent: July 30, 2019
    Assignee: Tokyo Electron Limited
    Inventors: Alok Ranjan, Vinayak Rastogi
  • Patent number: 10340137
    Abstract: A method of forming a thin film is described. The method includes treating at least a portion of a surface exposed on a substrate with an adsorption-promoting agent to alter a functionality of the exposed surface and cause subsequent adsorption of an organic precursor, and thereafter, adsorbing the organic precursor to the functionalized surface to form a carbon-containing film. Then, at least a portion of the surface of the carbon-containing film is exposed to an ion flux to mix the adsorbed carbon-containing film with the material of the underlying substrate and form a mixed film.
    Type: Grant
    Filed: July 24, 2017
    Date of Patent: July 2, 2019
    Assignee: TOKYO ELECTRON LIMITED
    Inventors: Peter Ventzek, Alok Ranjan
  • Patent number: 10312102
    Abstract: A method of etching is described. The method includes providing a substrate having a first material containing silicon nitride and a second material that is different from the first material, forming a first chemical mixture by plasma-excitation of a first process gas containing H and optionally a noble gas, and exposing the first material on the substrate to the first chemical mixture. Thereafter, the method includes forming a second chemical mixture by plasma-excitation of a second process gas containing N, F, O, and optionally a noble element, and exposing the first material on the substrate to the second plasma-excited process gas to selectively etch the first material relative to the second material.
    Type: Grant
    Filed: August 25, 2017
    Date of Patent: June 4, 2019
    Assignee: TOKYO ELECTRON LIMITED
    Inventors: Sonam D. Sherpa, Alok Ranjan