Study of Copper Diffusion Into Tantalum and Tantalum Diffusion Into Copper

Abstract

We have carried out direct diffusion measurements of Cu into Ta and Ta into Cu. Thin films of 50nm thickness of Cu were grown onto a thick Ta layer of 1 μm by Ionized Metal Plasma. Samples were annealed in a rapid thermal system from temperatures ranging from 400°C to 800°C for periods of 60s and 180s. The diffusion profile was performed using Secondary ion mass spectroscopy. The Cu diffusion coefficients in Ta can be described by 3.0246 × 10-15 exp(-0.1747eV/kT) at 60s and 2.7532 × 10-15 exp(-0.1737eV/kT) at 180s. The Ta diffusion coefficients in Cu can be described by 2.7532 × 10-15 exp(-0.1773eV/kT) at 60s and 2.1271 × 10-15 exp(-0.1753eV/kT) at 180s. To assure reliability, the extent of both diffusions should be considered in device design and processing.

ToF-SIMS Study of Carbon Diffusion in Co-Pt-TiO<SUB>2</SUB> Composite and Ruthenium Films

“…It is therefore believed that the diffusion in Ru was confined on surface. 10 The insignificant amount of carbon in Ru is explained by its grain structure as measured by XRD in Figure 6. There was a minimum (100) peak intensity (at 38.25 .…”

Use of lateral film structure for ultrathin diffusion barrier thermal stability study

“…However, its high diffusivity in Si and SiO 2 1-4 requires the replacement of the Al barrier (TiN) by a different barrier, so as to prevent a degradation of the dielectric quality. [8][9][10][11][12][13][14] This generates doubt on the effectiveness of Ta as a barrier when its thickness is 5 nm or less. 8,9 However, through various studies, Ta was found to be effective only within a certain temperature range, depending on the barrier thickness.…”

“…In most studies, [8][9][10][11][12][13][14][15][16] the sample film stack has Cu as the topmost layer of the stack, generally simulating the vertical film stack in interconnect systems. Some studies that made use of a Si 3 N 4 -passivated vertical film stack showed that the barrier failure temperature increased.…”

“…Some studies that made use of a Si 3 N 4 -passivated vertical film stack showed that the barrier failure temperature increased. 20 In spite of these studies, [8][9][10][11][12][13][14] the research value of the vertical film stack may not be applicable to the study of interconnect vias. 20 In spite of these studies, [8][9][10][11][12][13][14] the research value of the vertical film stack may not be applicable to the study of interconnect vias.…”

Ruhenium as diffusion barrier for carbon overcoat of magnetic recording media

“…6-10, which determines the type of diffusion mechanism involved in sample RU01, is almost flat. It is therefore believed that the diffusion in Ru was confined to the surface [163]. The insignificant amount of carbon in Ru is explained by its grain structure as measured by XRD in Fig.…”