USA: glass frit wafer bonding process patented

Delphi Technologies Inc., of Troy, Michigan has been assigned a US Patent for a method of glass frit bonding wafers to form a package, in which the width of the glass bond line between the wafers is m…

Delphi Technologies Inc., of Troy, Michigan has been assigned a US Patent for a method of glass frit bonding wafers to form a package, in which the width of the glass bond line between the wafers is minimized to reduce package size. The method was developed by Larry Lee Jordan and Douglas A. Knapp, both of Indiana. According to the U.S. Patent & Trademark Office: “The method entails the use of a glass frit material containing a particulate filler material that establishes the stand-off distance between wafers, instead of relying on discrete structural features on one of the wafers dedicated to this function.” An abstract of the invention, released by the Patent Office, said: “In addition, the amount of glass frit material used to form the glass bond line between wafers is reduced to such levels as to reduce the width of the glass bond line, allowing the overall size of the package to be minimized. To accommodate the variability associated with screening processes when low volume lines of paste are printed, the invention further entails the use of storage regions defined by walls adjacent the glass bond line to accommodate excess glass frit material without significantly increasing the width of the bond line. The storage regions also ensure adequate flow of glass frit material around electrical runners that cross the glass bond line, as well as into any isolation trenches surrounding the runners.” The inventors were issued U.S. Patent No. 6,879,048 on 12 April 2005. The original application was filed on 5 March 2003.