Patents by Inventor Nageshwer R. Bantu

Nageshwer R. Bantu 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).

  • Patent number: 5609989
    Abstract: Proton sponge, berberine, and cetyltrimethyl ammonium hydroxide base compounds are used as additives to chemically amplified photoresists based on modified polyhydroxystyrene (PHS). The base additives scavenge free acids from the photoresist in order to preserve the acid labile moieties on the modified PHS polymer. The base additives are well suited to industrial processing conditions, do not react with the photoacid compounds in the photoresist composition to form byproducts which would hinder photoresist performance, and extend the shelf-life of the photoresist composition. In addition, the proton sponge and berberine base additives have a different absorption spectra than the modified PHS polymer, therefore, the quantity of base additive within the photoresist can be easily assayed and controlled.
    Type: Grant
    Filed: June 6, 1995
    Date of Patent: March 11, 1997
    Assignee: International Business Machines, Corporation
    Inventors: Nageshwer R. Bantu, William R. Brunsvold, George J. Hefferon, Wu-Song Huang, Ahmad D. Katnani, Mahmoud M. Khojasteh, Ratnam Sooriyakumaran, Dominic C. Yang
  • Patent number: 5281723
    Abstract: Disclosed is a method of recovering a cyclic alkylene carbonate, such as propylene carbonate, from an effluent stream of a process in which the cyclic alkylene carbonate removes an organic photoresist material from a substrate. The effluent is a cyclic alkylene carbonate effluent, e.g., a propylene carbonate effluent, of the carbonate, water, and polymeric solids. In the recovery process the cyclic alkylene carbonate effluent is fed to a heat exchanger, and separated into (i) water and volatiles, and (ii) cyclic carbonate. This lowers the concentration of water in the cyclic alkylene carbonate to a level that is low enough to substantially avoid hydrolysis of cyclic alkylene carbonate to the corresponding glycol. The dewatered cyclic alkylene carbonate is evaporated to separate the cyclic alkylene carbonate from high boiling materials and polymeric solids. The dewatered cyclic alkylene carbonate is separated into (i) a cyclic alkylene carbonate fraction, and (ii) a photoresist solids fraction.
    Type: Grant
    Filed: August 4, 1992
    Date of Patent: January 25, 1994
    Assignee: International Business Machines
    Inventors: Nageshwer R. Bantu, Anilkumar C. Bhatt, Ross W. Keesler, Konstantinos Papathomas, Terry D. Sinclair, Jerome J. Wagner
  • Patent number: 5268260
    Abstract: Simple, environmentally friendly developers and strippers are disclosed for free radical-initiated, addition polymerizable resists, cationically cured resists and solder masks and Vacrel photoresists. In all cases both the developers and the strippers include gamma butyrolactone, propylene carbonate and benzyl alcohol, optionally also including a minor amount of methanol, ethanol, isopropyl alcohol, propylene glycol monomethylacetate, ethylene glycol monomethyl ether, formamide, nitromethane, propylene oxide, or methyl ethyl ketone, acetone and water.
    Type: Grant
    Filed: October 22, 1991
    Date of Patent: December 7, 1993
    Assignee: International Business Machines Corporation
    Inventors: Nageshwer R. Bantu, Anilkumar C. Bhatt, Ashwinkumar C. Bhatt, Joseph A. Kotylo, Gerald W. Jones, Robert J. Owen, Kostas Papathomas, Anaya K. Vardya