Patents by Inventor Osamu Hiroaki

Osamu Hiroaki 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: 4863829
    Abstract: A positive type photoresist composition comprising a novolak resin and O-quinone diazide compound, the novolak resin being one which is obtained by the addition condensation reaction of a phenol and formaldehyde which is performed in one stage by using as a catalyst an organic acid salt of a divalent metal which is more electropositive than hydrogen, or in two stages by using an acid catalyst in the subsequent stage, the phenol being at least one compound represented by the formula ##STR1## wherein R is hydrogen or an alkyl group of carbon number 1 to 4, the compound being such that the average carbon number in the substituent per one phenol nucelus is 0.5 to 1.5 and the ones with the substituent at the ortho- or para-position with respect to the hydroxyl group account for less than 50 mol %, is disclosed. The positive type photoresist composition of the invention has an improved resolving power, i.e., .gamma.-value.
    Type: Grant
    Filed: March 29, 1988
    Date of Patent: September 5, 1989
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Akihiro Furuta, Makoto Hanabata, Seimei Yasui, Osamu Hiroaki, Naoyoshi Jinno