Patents by Inventor Huma Ashraf
Huma Ashraf 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).
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Publication number: 20240006181Abstract: A plasma etch step anisotropically etches a silicon carbide semiconductor substrate through an opening to produce a feature. The plasma etch step generates a plasma from an etchant gas mixture that includes at least one fluorine-containing component and chlorine gas. The etchant gas mixture can further include SiCl4, an oxygen-containing component, and/or inert gas component.Type: ApplicationFiled: June 25, 2023Publication date: January 4, 2024Inventors: Huma Ashraf, Kevin Riddell, Alex Croot
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Publication number: 20230197457Abstract: An additive-containing aluminium nitride film containing an additive element selected from Sc, Y or Er is plasma etched through a mask for a period of time, t, with a plasma formed in a gaseous atmosphere having an associated gas pressure while an RF bias power is applied to the additive-containing aluminium nitride film. The gas pressure is reduced and/or the RF bias power is increased for a majority of the period of time t, so that the plasma etching becomes less chemical and more physical over a majority of the period of time, t.Type: ApplicationFiled: December 5, 2022Publication date: June 22, 2023Inventors: Alex Wood, Kevin Riddell, Huma Ashraf
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Publication number: 20230170188Abstract: An additive-containing aluminium nitride film is plasma etched. The additive-containing aluminium nitride film contains an additive element selected from scandium, yttrium or erbium. A workpiece is placed upon a platen within a plasma chamber. The workpiece includes a substrate having an additive-containing aluminium nitride film deposited thereon and a mask disposed upon the additive-containing aluminium nitride film, which defines at least one trench. A first etching gas is introduced into the chamber with a first flow rate, a second etching gas is introduced into the chamber with a second flow rate, and a plasma is established within the chamber to etch the additive-containing aluminium nitride film exposed within the trench. The first etching gas comprises boron trichloride and the second etching gas comprises chlorine. A ratio of the first flow rate to the second flow rate is greater than or equal to 1:1.Type: ApplicationFiled: November 8, 2022Publication date: June 1, 2023Inventors: Alex Huw Wood, Kevin Riddell, Huma Ashraf, Janet Hopkins
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Patent number: 11664232Abstract: A structure comprising a substrate and a component which forms involatile metal etch products is plasma etched. A structure comprising a substrate and a component which forms involatile metal etch products is provided. The structure is positioned on a support within a chamber having a first gas inlet arrangement comprising one or more gas inlets and a second gas inlet arrangement comprising one or more gas inlets. The structure is etched by performing a first plasma etch step using a first etch process gas mixture which is only introduced into the chamber through the first gas inlet arrangement. The structure is further etched by performing a second plasma etch step using a second etch process gas mixture which is only introduced into the chamber through the second gas inlet arrangement.Type: GrantFiled: November 15, 2020Date of Patent: May 30, 2023Assignee: SPTS Technologies LimitedInventors: Huma Ashraf, Kevin Riddell, Codrin Prahoveanu
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Patent number: 11489106Abstract: A structure comprising a semiconductor substrate and a layer of PZT (lead zirconate titanate) is etched by performing a first plasma etch step with a first etch process gas mixture. The first etch process gas mixture comprises at least one fluorine containing species. The first plasma etch step is performed so that involatile metal etch products are deposited onto interior surfaces of the chamber. The structure is further etched by performing a second plasma etch step with a second etch process gas mixture. The second etch process gas mixture comprises at least one fluorocarbon species. The second plasma etch step is performed so that a fluorocarbon polymer layer is deposited onto interior surfaces of the chamber to overlay involatile metal etch products deposited in the first plasma etch step and to provide a substrate on which further involatile metal etch products can be deposited.Type: GrantFiled: November 23, 2020Date of Patent: November 1, 2022Assignee: SPTS Technologies LimitedInventors: Huma Ashraf, Kevin Riddell, Codrin Prahoveanu
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Patent number: 11056379Abstract: A clamp assembly is for clamping an outer peripheral portion of a substrate to a support in a plasma processing chamber. An RF bias power is applied to the support during the plasma processing of the substrate. The clamp assembly includes an outer clamp member, and an inner clamp member which is received by the outer clamp member, the inner clamp member defining an aperture which exposes the substrate to the plasma processing. The outer clamp member has an inner portion terminating in an inner edge, wherein the inner portion is spaced apart from the inner clamp member.Type: GrantFiled: October 28, 2015Date of Patent: July 6, 2021Inventors: Anthony Barker, Huma Ashraf, Brian Kiernan
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Publication number: 20210193471Abstract: A structure comprising a substrate and a component which forms involatile metal etch products is plasma etched. A structure comprising a substrate and a component which forms involatile metal etch products is provided. The structure is positioned on a support within a chamber having a first gas inlet arrangement comprising one or more gas inlets and a second gas inlet arrangement comprising one or more gas inlets. The structure is etched by performing a first plasma etch step using a first etch process gas mixture which is only introduced into the chamber through the first gas inlet arrangement. The structure is further etched by performing a second plasma etch step using a second etch process gas mixture which is only introduced into the chamber through the second gas inlet arrangement.Type: ApplicationFiled: November 15, 2020Publication date: June 24, 2021Inventors: Huma Ashraf, Kevin Riddell, Codrin Prahoveanu
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Publication number: 20210193908Abstract: A structure comprising a semiconductor substrate and a layer of PZT (lead zirconate titanate) is etched by performing a first plasma etch step with a first etch process gas mixture. The first etch process gas mixture comprises at least one fluorine containing species. The first plasma etch step is performed so that involatile metal etch products are deposited onto interior surfaces of the chamber. The structure is further etched by performing a second plasma etch step with a second etch process gas mixture. The second etch process gas mixture comprises at least one fluorocarbon species. The second plasma etch step is performed so that a fluorocarbon polymer layer is deposited onto interior surfaces of the chamber to overlay involatile metal etch products deposited in the first plasma etch step and to provide a substrate on which further involatile metal etch products can be deposited.Type: ApplicationFiled: November 23, 2020Publication date: June 24, 2021Inventors: Huma Ashraf, Kevin Riddell, Codrin Prahoveanu
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Patent number: 11037793Abstract: According to the invention there is provided a method of plasma etching a silicon-based compound semiconductor substrate, the method comprising providing the substrate within an etch chamber and performing a cyclical process on the substrate, each cycle comprising supplying an etchant gas into the chamber, energising the gas into a plasma, and performing an etch step on the substrate using the plasma; and performing a desorption step, wherein during the desorption step, the only gas that is supplied into the etch chamber is an inert gas, so as to allow reactive species that have adsorbed to the surface of the substrate during the etch step to desorb from the surface of the substrate.Type: GrantFiled: June 20, 2019Date of Patent: June 15, 2021Assignee: SPTS Technologies LimitedInventors: Huma Ashraf, Kevin Riddell, Alex Wood
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Publication number: 20210175082Abstract: A substrate with a mask formed thereon is provided. The substrate is formed from a compound semiconductor material. A first plasma etch step is performed to anisotropically etch the substrate through the opening to produce a partially formed feature having a bottom surface comprising a peripheral region. A second plasma etch step is performed to anisotropically etch the bottom surface of the partially formed feature through the opening while depositing a passivation material onto the mask so as to reduce a dimension of the opening. The reduction of the dimension of the opening causes an attenuation in etching of the peripheral region thereby producing a fully formed feature having a bottom surface comprising a central region and an edge region. The central region is deeper than the edge region of the bottom surface of the fully formed feature.Type: ApplicationFiled: November 15, 2020Publication date: June 10, 2021Inventors: Huma Ashraf, Alex Croot, Kevin Riddell
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Patent number: 10899606Abstract: A method is for manufacturing a plurality of silicon microneedles which have a bevelled tip. The method includes providing a silicon substrate having a front face and a rear face, forming a first mask arrangement on the front face of the substrate, the first mask arrangement defining one or more gaps, and performing a SF6 based plasma etch of the front face through the gaps in the first mask arrangement to provide one or more etch features having a sloping face. The SF6 based plasma etch undercuts the first mask arrangement with an undercut that is at least 10% of the depth of a corresponding etch feature.Type: GrantFiled: June 15, 2018Date of Patent: January 26, 2021Assignee: SPTS Technologies LimitedInventors: Kerry Roberts, Huma Ashraf, Pey Fen Eng
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Publication number: 20190393044Abstract: According to the invention there is provided a method of plasma etching a silicon-based compound semiconductor substrate, the method comprising providing the substrate within an etch chamber and performing a cyclical process on the substrate, each cycle comprising supplying an etchant gas into the chamber, energising the gas into a plasma, and performing an etch step on the substrate using the plasma; and performing a desorption step, wherein during the desorption step, the only gas that is supplied into the etch chamber is an inert gas, so as to allow reactive species that have adsorbed to the surface of the substrate during the etch step to desorb from the surface of the substrate.Type: ApplicationFiled: June 20, 2019Publication date: December 26, 2019Inventors: HUMA ASHRAF, KEVIN RIDDELL, ALEX WOOD
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Patent number: 10431436Abstract: A method and system are for monitoring and controlling deformation of a wafer substrate during a plasma etching of the wafer substrate. The method includes disposing a wafer substrate on a platen assembly within a process chamber so that an entire upper surface of the wafer is exposed, passing a process gas into the process chamber, applying a radio frequency bias voltage to the platen assembly, generating a plasma within the process chamber, monitoring a voltage difference between the platen assembly and the process chamber, during the etch process, and attenuating or extinguishing the plasma to prevent further etching once a threshold monitored voltage is reached.Type: GrantFiled: August 30, 2017Date of Patent: October 1, 2019Assignee: SPTS TECHNOLOGIES LIMITEDInventors: Huma Ashraf, Kevin Riddell, Roland Mumford, Grant Baldwin
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Publication number: 20180362334Abstract: A method is for manufacturing a plurality of silicon microneedles which have a bevelled tip. The method includes providing a silicon substrate having a front face and a rear face, forming a first mask arrangement on the front face of the substrate, the first mask arrangement defining one or more gaps, and performing a SF6 based plasma etch of the front face through the gaps in the first mask arrangement to provide one or more etch features having a sloping face. The SF6 based plasma etch undercuts the first mask arrangement with an undercut that is at least 10% of the depth of a corresponding etch feature.Type: ApplicationFiled: June 15, 2018Publication date: December 20, 2018Inventors: Kerry Roberts, Huma Ashraf, Pen Fen Eng
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Publication number: 20180144911Abstract: A method and system are for monitoring and controlling deformation of a wafer substrate during a plasma etching of the wafer substrate. The method includes disposing a wafer substrate on a platen assembly within a process chamber so that an entire upper surface of the wafer is exposed, passing a process gas into the process chamber, applying a radio frequency bias voltage to the platen assembly, generating a plasma within the process chamber, monitoring a voltage difference between the platen assembly and the process chamber, during the etch process, and attenuating or extinguishing the plasma to prevent further etching once a threshold monitored voltage is reached.Type: ApplicationFiled: August 30, 2017Publication date: May 24, 2018Inventors: HUMA ASHRAF, KEVIN RIDDELL, ROLAND MUMFORD, GRANT BALDWIN
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Patent number: 9601341Abstract: A method of etching a feature in a substrate includes forming a mask structure over the substrate, the mask structure defining at least one re-entrant opening, etching the substrate through the opening to form the feature using a cyclic etch and deposition process, and removing the mask.Type: GrantFiled: December 19, 2014Date of Patent: March 21, 2017Assignee: SPTS Technologies LimitedInventor: Huma Ashraf
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Publication number: 20160126129Abstract: A clamp assembly is for clamping an outer peripheral portion of a substrate to a support in a plasma processing chamber. An RF bias power is applied to the support during the plasma processing of the substrate. The clamp assembly includes an outer clamp member, and an inner clamp member which is received by the outer clamp member, the inner clamp member defining an aperture which exposes the substrate to the plasma processing. The outer clamp member has an inner portion terminating in an inner edge, wherein the inner portion is spaced apart from the inner clamp member.Type: ApplicationFiled: October 28, 2015Publication date: May 5, 2016Inventors: ANTHONY BARKER, HUMA ASHRAF, BRIAN KIERNAN
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Publication number: 20150179468Abstract: A method of etching a feature in a substrate includes forming a mask structure over the substrate, the mask structure defining at least one re-entrant opening, etching the substrate through the opening to form the feature using a cyclic etch and deposition process, and removing the mask.Type: ApplicationFiled: December 19, 2014Publication date: June 25, 2015Inventor: HUMA ASHRAF
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Patent number: 9040427Abstract: A method of plasma etching a silicon carbide workpiece includes forming a mask on a surface of the silicon carbide workpiece, performing an initial plasma etch on the masked surface using a first set of process conditions, wherein the plasma is produced using an etchant gas mixture which includes i) oxygen and ii) at least one fluorine rich gas which is present in the etchant gas mixture at a volume ratio of less than 50%, and subsequently performing a bulk plasma etch process using a second set of process conditions which differ from the first set of process conditions.Type: GrantFiled: October 1, 2013Date of Patent: May 26, 2015Assignee: SPTS Technologies LimitedInventors: Huma Ashraf, Anthony Barker
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Publication number: 20140097153Abstract: a method of plasma etching a silicon carbide workpiece includes forming a mask on a surface of the silicon carbide workpiece, performing an initial plasma etch on the masked surface using a first set of process conditions, wherein the plasma is produced using an etchant gas mixture which includes i) oxygen and ii) at least one fluorine rich gas which is present in the etchant gas mixture at a volume ratio of less than 50%, and subsequently performing a bulk plasma etch process using a second set of process conditions which differ from the first set of process conditions.Type: ApplicationFiled: October 1, 2013Publication date: April 10, 2014Applicant: SPTS TECHNOLOGIES LIMITEDInventors: Huma ASHRAF, Anthony BARKER