Enhancement effects of diffusion and impurity correlation coefficient in diluted Cu(Sn) alloys

Abstract

The solvent and solute enhancement factors in Cn(Sn) alloys are studied for Sn concentrat,ions up to 2.86 at?; in the temperature ranges of 797.3 to 921.4 "C and of 759.4 to 908.4 "C. respectively. The calculated enhancement factors are b?" = 56.5 t.0 38.0 and bi' = 3893 to 2349 for solvent diffusion and bf"= 36.8 to 37.8 for solute diffusion in the corresponding temperature ranges. In order t o determine the correlation factor, fi. of impiirit,y diffusion a modified method is proposed. The resiilt,ing correlation coefficients aref? = 0.31 at T = 797.3 "C andf, = 0.46 a t T = 921.4 "C. Solvent-wid Solu t,e-Erhohiingsfaktoren aerden in Cu(Sn)-Legiernngen fur Zinnkonzentrationen zwischen 0 iind 2,86 At?!, in den Temperatiirbereichen 797.3 und 921,4 "C, sowie 759,4 und 908,4 "C untersucht. Die berechneten Erhohungsfaktoren sind by" = 66.5 bis 38,O und 7 1 ; ' ' = 3893 bis 2349 fur ,,Solvent"-Diffusion und b:" = 35,8 bis 37,8 fur ,.Solute"-Diffusion in den genaniiten Temperaturbereichen. Zur Ermittlung des Korrelationsfakt,ors ii der Fremddiffusion wird eine modifizierte Methode vorgeschlagen. Die erhakenen Korrelat ionsfakt,oren sind f 2 = 0,31 bei T = = 797,3 "C undf? = 0,46 bei T = 921,4 "C.

Electromigration of Cu/low dielectric constant interconnects

“…The effect of Sn solute in bulk Cu is different from that in thin films. In bulk Cu(Sn) samples, Sn solute enhances Cu and Sn lattice diffusion [95], while solute Sn decreases Cu diffusion in Cu(Sn) grain boundaries of thin films [74]. These observed behaviors are similar to Pd in Cu(Pd) [77] and Au in Au(Ta) [96] studies.…”

On the Determination of Enhancement Factors of Solvent Diffusion

“…Solvent diffusion coefficients D& in the system CuSn [2,151 logarithmically plotted vs. tin concentration Nsn. 0 [2], o [15] Enhancement factor b, obtained from (22) and b, = f b2, and Gibbs free energy of binding 69, according t o (9) and (13) for the systems AgAs [l], AgSn [6, 141, The tendency for dissociation ofvacancy-impurity complexes increases with increasing temperature, so that decreasing enhancement factors are to be expected. I n all four cases this expectation agrees with the temperature dependence, which is found by the b, values given in Table 4.…”

The stress-induced escape of migrating aluminium from silicide interconnects

“…Aluminium metallization has been widely used for interconnect lines in silicon based interconnects. The adverse effect of matter migration due to momentum exchange between the conduction electrons and the matrix or alloying atoms has been studied extensively [1][2][3][4][5]. The existence of an electromigration threshold in pure aluminium interconnects was investigated first by Blech and Herring [6,7].…”