Patents by Inventor Ramanujapuram A. Srinivas
Ramanujapuram A. Srinivas 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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Patent number: 10239160Abstract: Systems and methods for material singulation. According to some embodiments, methods for material singulation may include applying a first laser output to the material, the first laser output causing a modification of a material property of the material when exposed to the first laser output; and applying a second laser output to the material that was exposed to the first laser output to cause singulation of the material in such a way that surfaces created by the singulation of the material are substantially free from defects.Type: GrantFiled: September 21, 2011Date of Patent: March 26, 2019Assignee: Coherent, Inc.Inventors: Michael Mielke, Ramanujapuram A. Srinivas, Tim Booth, Thor Wilbanks
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Publication number: 20180161918Abstract: Methods of and devices for forming edge chamfers and through holes and slots on a material that is machined using a laser, such as an ultrafast laser. The shaped material has predetermined and highly controllable geometric shape and/or surface morphology. Further, a method of and a device for preventing re-deposition of the particles on a material that is machined using a laser, such as an ultrafast laser. A fluid is used to wash off the particles generated during the laser machining process. The fluid can be in a non-neutral condition, with one or more chemical salts added, or a condition allowing the coagulation of the particles in the fluid, such that the particles can be precipitated to avoid the reattachment to the machined substrate.Type: ApplicationFiled: February 6, 2018Publication date: June 14, 2018Inventors: Ramanujapuram A. SRINIVAS, David M. GAUDIOSI, Timothy BOOTH, Michael SHIRK, Eric JUBAN, Michael MIELKE
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Patent number: 9919380Abstract: Methods of and devices for forming edge chamfers and through holes and slots on a material that is machined using a laser, such as an ultrafast laser. The shaped material has predetermined and highly controllable geometric shape and/or surface morphology. Further, a method of and a device for preventing re-deposition of the particles on a material that is machined using a laser, such as an ultrafast laser. A fluid is used to wash off the particles generated during the laser machining process. The fluid can be in a non-neutral condition, with one or more chemical salts added, or a condition allowing the coagulation of the particles in the fluid, such that the particles can be precipitated to avoid the reattachment to the machined substrate.Type: GrantFiled: February 21, 2014Date of Patent: March 20, 2018Assignee: Coherent, Inc.Inventors: Ramanujapuram A. Srinivas, David M. Gaudiosi, Timothy Booth, Michael Shirk, Eric Juban, Michael Mielke
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Patent number: 9120181Abstract: Systems and methods for processing, selectively ablating, and singulating layered materials. According to some embodiments, methods for selectively ablating a layered material may include selectively varying a wavelength of at least a portion of a primary ultrafast laser beam to create a secondary ultrafast laser beam with a second wavelength, the primary ultrafast laser beam being configured to ablate a layer of the layered material, the secondary ultrafast laser beam being configured to ablate an additional layer of the layered material and applying the first and second ultrafast laser beams to the layered material to create a singulated product.Type: GrantFiled: September 16, 2011Date of Patent: September 1, 2015Assignee: COHERENT, INC.Inventors: Ramanujapuram A. Srinivas, Michael Greenberg, David Gaudiosi, Michael Mielke, Tim Booth
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Patent number: 9114482Abstract: Systems and methods for laser based processing of layered materials. Methods may include selectively adjusting ultrafast laser output of an ultrafast laser device based upon one or more physical attributes of a layer of the layered material, applying the ultrafast laser output of the ultrafast laser device to the layer of the layered material along a tool path to ablate the layer along the tool path, and then re-executing the steps to ablate one or more additional layers, the re-execution occurring for each distinct layer of the layered material that is to be ablated.Type: GrantFiled: September 16, 2011Date of Patent: August 25, 2015Assignee: Raydiance, Inc.Inventors: Ramanujapuram A. Srinivas, Michael Greenberg, David Gaudiosi, Michael Mielke, Tim Booth
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Publication number: 20140239552Abstract: Methods of and devices for forming edge chamfers and through holes and slots on a material that is machined using a laser, such as an ultrafast laser. The shaped material has predetermined and highly controllable geometric shape and/or surface morphology. Further, a method of and a device for preventing re-deposition of the particles on a material that is machined using a laser, such as an ultrafast laser. A fluid is used to wash off the particles generated during the laser machining process. The fluid can be in a non-neutral condition, with one or more chemical salts added, or a condition allowing the coagulation of the particles in the fluid, such that the particles can be precipitated to avoid the reattachment to the machined substrate.Type: ApplicationFiled: February 21, 2014Publication date: August 28, 2014Applicant: Raydiance, Inc.Inventors: Ramanujapuram A. Srinivas, David M. Gaudiosi, Timothy Booth, Michael Shirk, Eric Juban, Michael Mielke
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Publication number: 20140027951Abstract: The method of and device for cutting brittle materials with tailored edge shape and roughness are disclosed. The methods can include directing one or more tools to a portion of brittle material causing separation of the material into two or more portions, where the as-cut edge has a predetermined and controllable geometric shape and/or surface morphology. The one or more tools can comprise energy (e.g., a femtosecond laser beam or acoustic beam) delivered to the material without making a physical contact.Type: ApplicationFiled: July 30, 2013Publication date: January 30, 2014Applicant: Raydiance, Inc.Inventors: Ramanujapuram A. Srinivas, David M. Gaudiosi, Michael R. Greenberg, Jeffrey Albelo, Tim Booth, Michael Shirk, Michael Mielke
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Publication number: 20130068736Abstract: Systems and methods for material singulation. According to some embodiments, methods for material singulation may include applying a first laser output to the material, the first laser output causing a modification of a material property of the material when exposed to the first laser output; and applying a second laser output to the material that was exposed to the first laser output to cause singulation of the material in such a way that surfaces created by the singulation of the material are substantially free from defects.Type: ApplicationFiled: September 21, 2011Publication date: March 21, 2013Inventors: Michael Mielke, Ramanujapuram A. Srinivas, Tim Booth, Thor Wilbanks
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Publication number: 20120156875Abstract: Systems and methods for laser based processing of layered materials. Methods may include selectively adjusting ultrafast laser output of an ultrafast laser device based upon one or more physical attributes of a layer of the layered material, applying the ultrafast laser output of the ultrafast laser device to the layer of the layered material along a tool path to ablate the layer along the tool path, and then re-executing the steps to ablate one or more additional layers, the re-execution occurring for each distinct layer of the layered material that is to be ablated.Type: ApplicationFiled: September 16, 2011Publication date: June 21, 2012Inventors: Ramanujapuram A. Srinivas, Michael Greenberg, David Gaudiosi, Michael Mielke, Tim Booth
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Publication number: 20120152915Abstract: Systems and methods for processing, selectively ablating, and singulating layered materials. According to some embodiments, methods for selectively ablating a layered material may include selectively varying a wavelength of at least a portion of a primary ultrafast laser beam to create a secondary ultrafast laser beam with a second wavelength, the primary ultrafast laser beam being configured to ablate a layer of the layered material, the secondary ultrafast laser beam being configured to ablate an additional layer of the layered material and applying the first and second ultrafast laser beams to the layered material to create a singulated product.Type: ApplicationFiled: September 16, 2011Publication date: June 21, 2012Inventors: Ramanujapuram A. Srinivas, Michael Greenberg, David Gaudiosi, Michael Mielke, Tim Booth
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Patent number: 6573181Abstract: A method of forming a contact in an integrated circuit including forming a dielectric layer over a silicon substrate, etching a contact hole through the dielectric layer, exposing the etched contact hole to a plasma formed from a preclean gas comprising nitrogen trifluoride and helium and, thereafter, depositing a titanium layer within the contact hole by a plasma CVD process, where the plasma CVD process heats the substrate to a temperature less than or equal to 650° C.Type: GrantFiled: October 26, 2000Date of Patent: June 3, 2003Assignee: Applied Materials, Inc.Inventors: Ramanujapuram A. Srinivas, Mohan K. Bhan, Jennifer Kopp
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Patent number: 6548402Abstract: A method of forming a titanium nitride (TiN) layer using a reaction between ammonia (NH3) and titanium tetrachloride (TiCl4). In one embodiment, an NH3:TiCl4 ratio of about 8.5 is used to deposit a TiN layer at a temperature of about 500° C. at a pressure of about 20 torr. In another embodiment, a composite TiN layer is formed by alternately depositing TiN layers of different thicknesses, using process conditions having different NH3:TiCl4 ratios. In one preferred embodiment, a TiN layer of less than about 20 Å is formed at an NH3:TiCl4 ratio of about 85, followed by a deposition of a thicker TiN layer at an NH3:TiCl4 ratio of about 8.5. By repeating the alternate film deposition using the two different process conditions, a composite TiN layer is formed. This composite TiN layer has an improved overall step coverage and reduced stress, compared to a standard TiN process, and is suitable for small geometry plug fill applications.Type: GrantFiled: June 11, 1999Date of Patent: April 15, 2003Assignee: Applied Materials, Inc.Inventors: Shulin Wang, Ming Xi, Frederick Wu, Ramanujapuram A. Srinivas, Yehuda Demayo, Zvi Lando, Mei Chang, Russell C. Ellwanger
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Publication number: 20030049931Abstract: Refractory metal nitride layers for integrated circuit fabrication are described. The refractory metal nitride layer may be formed by sequentially chemisorbing alternating monolayers of a nitrogen-containing compound and a refractory metal compound onto a substrate. A composite refractory metal nitride layer is also described. The composite refractory metal nitride layer may be formed by sequentially chemisorbing monolayers of a nitrogen-containing compound and two or more refractory metal compounds onto a substrate.Type: ApplicationFiled: September 19, 2001Publication date: March 13, 2003Applicant: APPLIED MATERIALS, INC.Inventors: Jeong Soo Byun, Lin Yin, Frederick C. Wu, Ramanujapuram A. Srinivas, Avgerinos Gelatos, Alfred W. Mak, Mei Chang, Moris Kori, Ashok K. Sinha
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Patent number: 6524952Abstract: A method of forming a silicide layer in contact with a silicon substrate. The method comprises forming the silicide layer by supplying a silicon-containing source that is different from the silicon substrate, such that the silicon in the silicide layer originates primarily from the silicon-containing source.Type: GrantFiled: June 20, 2000Date of Patent: February 25, 2003Assignee: Applied Materials, Inc.Inventors: Ramanujapuram A. Srinivas, Brian Metzger, Shulin Wang, Frederick C. Wu
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Publication number: 20020192396Abstract: A method of forming a film structure (e.g., film stack) comprising titanium (Ti) and titanium nitride (TiN) films is disclosed. In one aspect of the invention, a titanium silicide (TiSix) layer is formed on a Ti film, followed by deposition of a TiN film on the TiSix layer. The TiSix layer protects the underlying Ti film from chemical attack by TiCl4-based chemistry during subsequent TiN layer deposition. In another aspect of the invention, a cap layer of TiN is deposited between the Ti and TiN layers of a Ti/TiN film structure. The TiN cap layer inhibits chlorine migration from the overlying TiN layer into an underlying contact region, such as, for example, the source or drain of a transistor.Type: ApplicationFiled: May 11, 2000Publication date: December 19, 2002Inventors: Shulin Wang, Mei Chang, Ramanujapuram A. Srinivas, Avgerinos Gelatos
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Patent number: 6432479Abstract: Method for passivating a layer of titanium that has been deposited on a substrate in a reaction chamber to coat the titanium thereby reducing the likelihood of contamination by byproducts of the deposition process or ambient oxygen or similar reactants. The method includes adding a flow of hydrogen and a flow of nitrogen to the chamber. The flows of hydrogen and nitrogen are approximately 800 sccm and continue for approximately 10-30 seconds respectively. The method may further comprise the step of forming a nitrogen plasma in the chamber for approximately 10 seconds wherein such case the flows of hydrogen and nitrogen continue for approximately 8 seconds respectively. The plasma is formed by applying RF power to an electrode located within said chamber or by a remote plasma source and channeled to said reactor chamber. Alternately, the passivation layer may be formed just by using a nitrogen plama alone for approximately 10-30 seconds at the same RF power level.Type: GrantFiled: October 29, 1998Date of Patent: August 13, 2002Assignee: Applied Materials, Inc.Inventors: Mei Chang, Ramanujapuram A. Srinivas, Li Wu
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Publication number: 20020064598Abstract: A method of forming a titanium nitride (TiN) layer using a reaction between ammonia (NH3) and titanium tetrachloride (TiCl4). In one embodiment, an NH3:TiCl4 ratio of about 8.5 is used to deposit a TiN layer at a temperature of about 500° C. at a pressure of about 20 torr. In another embodiment, a composite TiN layer is formed by alternately depositing TiN layers of different thicknesses, using process conditions having different NH3:TiCl4 ratios. In one preferred embodiment, a TiN layer of less than about 20 Å is formed at an NH3:TiCl4 ratio of about 85, followed by a deposition of a thicker TiN layer at an NH3:TiCl4 ratio of about 8.5. By repeating the alternate film deposition using the two different process conditions, a composite TiN layer is formed. This composite TiN layer has an improved overall step coverage and reduced stress, compared to a standard TiN process, and is suitable for small geometry plug fill applications.Type: ApplicationFiled: June 11, 1999Publication date: May 30, 2002Inventors: SHULIN WANG, MING XI, FREDERICK WU, RAMANUJAPURAM A. SRINIVAS, YEHUDA DEMAYO, ZVI LANDO, MEI CHANG, RUSSELL C. ELLWANGER
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Publication number: 20010003015Abstract: Method for passivating a layer of titanium that has been deposited on a substrate in a reaction chamber to coat the titanium thereby reducing the likelihood of contamination by byproducts of the deposition process or ambient oxygen or similar reactants. The method includes adding a flow of hydrogen and a flow of nitrogen to the chamber. The flows of hydrogen and nitrogen are approximately 800 sccm and continue for approximately 10-30 seconds respectively. The method may further comprise the step of forming a nitrogen plasma in the chamber for approximately 10 seconds wherein such case the flows of hydrogen and nitrogen continue for approximately 8 seconds respectively. The plasma is formed by applying RF power to an electrode located within said chamber or by a remote plasma source and channeled to said reactor chamber. Alternately, the passivation layer may be formed just by using a nitrogen plama alone for approximately 10-30 seconds at the same RF power level.Type: ApplicationFiled: October 29, 1998Publication date: June 7, 2001Inventors: MEI CHANG, RAMANUJAPURAM SRINIVAS, LI WU
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Patent number: 6242347Abstract: A method for the in situ cleaning of a semiconductor deposition chamber utilized for the deposition of a semiconductor material such as titanium or titanium nitride comprising, between wafers, introducing chlorine gas into the chamber at elevated temperature, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. A two-stage between wafer cleaning process is carried out by introducing chlorine into the chamber at elevated temperature, thereafter initiating a plasma without removing the chlorine, purging the chamber with an inert gas and evacuating it before introduction of the next wafer. In a preferred embodiment, a thin protective film of titanium is deposited on the inner surfaces of the chamber prior to utilizing the chamber for the deposition of such material. The protective layer is replenished following each two-stage cleaning.Type: GrantFiled: September 30, 1998Date of Patent: June 5, 2001Assignee: Applied Materials, Inc.Inventors: Anand Vasudev, Toshio Itoh, Ramanujapuram A. Srinivas, Frederick Wu, Li Wu, Brian Boyle, Mei Chang
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Patent number: 6193813Abstract: A method of processing a substrate, such as a semiconductor wafer, in a vacuum processing chamber includes the steps of depositing a material on a surface of the substrate using a gas mixture, and purging the chamber of residual gases by flowing SiH4 into the chamber. Preferably, WSix is deposited on a semiconductor wafer using a mixture comprising WF6, dichlorosilane and a noble gas, and the chamber is subsequently purged of residual WF6 and dichlorosilane by flowing SiH4 into the chamber. A further method of processing a substrate in a vacuum processing chamber includes the step of conditioning the chamber by flowing SiH4 into the chamber prior to depositing a material on the surface of the substrate. Semiconductor wafers processed according to the inventive method are characterized by more uniform sheet resistance values and reduced film stress.Type: GrantFiled: September 28, 1998Date of Patent: February 27, 2001Assignee: Applied Materials, Inc.Inventors: Meng Chu Tseng, Mei Chang, Ramanujapuram A. Srinivas, Klaus-Dieter Rinnen, Moshe Eizenberg, Susan Telford