Electromigration study in eutectic SnPb solder by edge displacement technique

• Main Authors: Chou. Chung-Kuang, 周重光
• Other Authors: Chen Chih
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/d5pm7p

碩士 === 國立交通大學 === 材料科學與工程系所 === 92 === In this study, we have successfully developed a technique that can precisely measure the important parameters of solder electromigration. By applying currents in the Blech specimen and by measuring the depletion volume at appropriate conditions, electromigration flux and other electromigration parameters can be obtained. We have developed a technique to fabricate solder Blech specimens, in which the depletion volume caused by electromigration can be measured precisely. Solder Blech specimens were fabricated on patterned Cu/Ti films in Si trenches. Electromigration eutectic PbSn Blech structure has been investigated. Depletion occurred at the cathode end of the Blech sample, and hillocks were observed at the anode end for most stressing conditions. By employing atomic force microscope to measure the depletion volume on the cathode end, the electromigration rate can be measured. Drift velocity was measured at the current density ranging from 9.1 x 103 to 9.7 x 104 A/cm2 at 80, 100, and 120 �aC. The drift velocity increased when the applied current increased. The calculated threshold current density is 1.2*10^3 A/cm^2 at 80℃, 1.8*10^3 A/cm^2 at 100 ℃, and 2.9*10^3 A/cm^2 at 120℃, respectively. The measured activation energy was 0.34 eV. With the activation energy, the values of D0Z* was calculated to be -9.71 �e 106 cm2/sec.