Patents by Inventor George Joseph Hefferon

George Joseph Hefferon 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).

  • Acid Scavengers for use in chemically amplified photoresists
    Patent number: 5733705
    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: October 11, 1996
    Date of Patent: March 31, 1998
    Assignee: International Business Machines Corporation
    Inventors: Nageshwer Rao Bantu, William Ross Brunsvold, George Joseph Hefferon, Wu-Song Huang, Ahmad D. Katnani, Mahmoud M. Khofasteh, Ratnam Sooriyakumaran, Dominic Changwon Yang
  • Acid scavengers for use in chemically amplified photoresists
    Patent number: 5667938
    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: October 11, 1996
    Date of Patent: September 16, 1997
    Assignee: International Business Machines Corporation
    Inventors: Nageshwer Rao Bantu, William Ross Brunsvold, George Joseph Hefferon, Wu-Song Huang, Ahmad D. Katnani, Mahmoud M. Khojasteh, Ratnam Sooriyakumaran, Dominic Changwon Yang