Figure 1
Abundant Ag hillocks formed on a sputtered Ag film, which was covered with a dummy Si chip and annealed at 250 °C under the ambient atmosphere for 1 h: (A) A top-view secondary electron image (SEI) of abundant Ag hillocks; and (B) The cross-sectional transmission electron microscope (TEM) micrograph of an individual abundant Ag hillock. Optical micrographs of patterned abundant Ag hillocks formed on a sputtered Ag film after being annealed at 250 °C for 1 h at (C) the “covered areas, i.e., inverse areas of NCKU” under the ambient atmosphere and (D) the “uncovered areas, i.e., ISIR/Osaka University” under an ultra-high vacuum condition (P < 10−2 Pa).
