Stress migration
Encyclopedia
Stress Migration is a failure mechanism that often occurs in IC metallization (aluminum, copper
). Voids form as result of vacancy migration driven by the hydrostatic stress gradient. Large voids may lead to open circuit or unacceptable resistance increase that impededs the IC performance. Stress Migration is often referred as Stress Voiding, Stress Induced Voiding or SIV.
High temperature processing of copper dual damascene structures leaves the copper with a large tensile stress due to a mismatch in coefficient of thermal expansion of the materials involved. The stress can relax with time through the diffusion of vacancies leading to the formation of voids and ultimately open circuit failures.
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
). Voids form as result of vacancy migration driven by the hydrostatic stress gradient. Large voids may lead to open circuit or unacceptable resistance increase that impededs the IC performance. Stress Migration is often referred as Stress Voiding, Stress Induced Voiding or SIV.
High temperature processing of copper dual damascene structures leaves the copper with a large tensile stress due to a mismatch in coefficient of thermal expansion of the materials involved. The stress can relax with time through the diffusion of vacancies leading to the formation of voids and ultimately open circuit failures.