Adherence of Fine Wires : Solution by Energy Minimum Principle and Nano Adhesional Bonding(Physics, Processes, Instruments & Measurements)
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Surface activated adhesional elastic contact solution between cylindrical bodies (wires) is deduced by energy minimum principle. The energy difference of Δγ=2γ_s-γ_i makes the contact width greater than Hertz's solution, where γ_s is the surface energy and γ_i is the interface energy at the contact area. The adhesional contact width a_j is given by [numerical formula] where k is expressed by k=(k_1+k_2)/2. Here, k_1 and k_2 are the elastic constants of two cylindrical bodies (or fine wires), R_1 and R_2 are the radii of two cylinders, R=(R_1+R_2)/2, and f is the applied force per unit length of cylinders. The adhesional elastic contact width a_j without load (f=0) is given by a_j=α・R^<2/3>・(k・Δγ)^<1/3>, where α is the constant and α=4^<2/3> for wire-wire contact with a same radius, α=4 for wire-plane contact and α=4^<5/6> for wire-rigid plane contact. The contact ratio a_j/R increases as R decreases, because a_j/R∝R^<-1/3>. It is suggested that heatless and pressureless nano-order interconnection is possible. Also, the possibility of nano adhesional bonding of very fine Au wire is discussed, taking into account some calculated results. Futher, an experimental evidence of Au wire adhesional bonding is shown.
- Transactions of JWRI
Transactions of JWRI 30(2), 23-31, 2001-12