Appeal No. 1998-2948
Application 08/400,861
Joshi discloses that aluminum and its alloys, such as
Al-Cu, have been the most common choices for metallization of
silicon based integrated circuits, but that most solute
additions to metals such as aluminum decrease its electrical
conductivity (p. 1480, left col.). Joshi states (p. 1480,
left col.): "Addition of elements with low solid solubility is
an approach to achieve metallization with improved
characteristics without undue deterioration in electrical
conductivity." Joshi further states (p. 1480, left col.):
"Many rare earth elements such as Ce and Sm have relatively
low solid solubilities in aluminum and are potential
beneficiaries to the metallization system when added in small
quantities." Joshi discloses an Al-1 wt% (0.29 at%) Sm
metallization alloy which is sputter deposited. The "Al-Sm
metallization exhibits very favorable properties, namely, low
resistivity and good thermal stability including hillock
growth resistance, for potential integrated circuit
applications" (abstract).
Yamamoto discloses electrodes for semiconductors which
resist hillock formation and have a specific resistance of
20 µS·cm or below which can be used as electrodes for
- 5 -
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: November 3, 2007