A novel application of anodic bonding for electrical interconnect and its parameter characterization

In this paper, Si-Au/Pt/Ti contact structure is fabricated using anodic bonding to realize the electrical interconnect. In order to evaluate the quality of contact structure, the contact resistance is extracted. At first, the cross-bridge Kelvin method is optimized and a new four-terminal bonded vertical Kelvin test structure is presented to directly and precisely measure the contact resistance. A two-dimensional resistor network model is established to obtain the relationship between the contact resistance and the measured resistance. Then the fabricated test structure is tested and moreover the contact resistance of the bonded Si/Au/Pt/Ti contacts is extracted from the current-voltage characteristic curves. Data obtained from the test indicate that the bonded contact is ohmic contact and the average value of R_C range from 19.7 to 48.3¿ when the contact area, A_C, is larger than 20*20¿m² with contact length, L, longer than 20¿m; whereas, when A_C is small than 20*20¿m², the contact is not reliable ohmic contact and the I-V characteristic is not stable.