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The shrinking line-to-line spacing in interconnect systems for advanced integrated circuit technology and the use of lower dielectric constant materials create the need for tools to evaluate the interconnect dielectric reliability. A multi-temperature, dual-ramp-rate voltage-ramp-to-breakdown methodology is presented and used here to extract important dielectric-breakdown parameters accurately for minimum-spaced metal lines. It is demonstrated that correction for the true minimum line-to-line spacing distributions become critically important and that the minimum spacing can be extracted electrically and compares favorably to electron microscopy cross sections. The spacing-corrected breakdown field distributions, at various temperatures, for the organosilicate material tested, indicated a very low apparent zero-field activation energy (0.14±0.02 eV) and an apparent field-acceleration parameter γ=4.1±0.3 cm/MV that has little or no temperature dependence. Constant-voltage time-dependent-dielectric-breakdown measurements were found to agree well with these observations. [ABSTRACT FROM AUTHOR]

Illustrates the development of a three-dimensional analytical solution as well as experimental verification of the thermoelastically induced deformation in a substrate-constrained thin polymeric film. Multireflection of the thin polymeric film; Relative distance measurement at a modulation frequency; Comparison of temperature modulation to elastic deformation; Discussion of the interfacial thermal resistance.

Part I. Deals with a study which used the photothermal displacement technique in measuring the out-of-plane thermal diffusivity in free-standing polymer thin films. Theoretical framework of the study; Description of the experimental setup of the study; Description of the displacement slope phase angle versus frequency measurement; Result of the thermal anisotropy analysis; Conclusion.

Electromigration studies on Cu interconnects are reviewed. Some history and more recent results are discussed along with a description of the present interpretations of the active mass transport mechanisms involved in Cu electromigration. The issue of the dual-damascene process and its potential effect on EM reliability is described with special focus on the peculiarities of the dual-damascene interconnect architecture compared to more conventional subtractively etched Al-based interconnects. Experiments performed on dual-damascene interconnects that highlight electromigration reliability issues such as early failure, a tentative explanation for via electromigration failure, and the Blech effect, are summarized. Emphasis is placed on an experimental methodology that uses large interconnect ensembles in a multi-link configuration. Such a large scale study of nearly 10 000 interconnects has shown statistical evidence of bimodal failure behavior consistent with the presence of a weak and strong failure mode, which have been identified as voiding, respectively, within the via and the trench at the cathode end of an interconnect. A multi-link approach has also demonstrated a length-dependent distribution of failures that yields a (j · L)[sub c] product value of about 9000 A/cm in dual-damascene Cu/oxide interconnections and is consistent with mass transport that is controlled by the presence of extended defects within Cu such as grain boundaries, interfaces, and/or surfaces. Because the future in microelectronics usually means now, electromigration studies on Cu have progressed rapidly since its identification as the future microelectronics metallization of the present. Much of the literature shows a range of observed EM activation energies. The values appear to depend on Cu deposition and/or preparation methods and can indicate the wide variety of pathways available for EM damage formation. Which mechanism is dominant in a given instance can depend on... [ABSTRACT FROM AUTHOR]

Electromigration (EM) reliability was investigated for Cu/porous low k interconnects. The porous low k dielectric was a methylsilsesquioxane (MSQ) based spin-on organosilicate material with k of 2.2. The activation energy for EM failure was found to be about 0.9 eV for Cu/porous MSQ between 208 and 367°C, which is commonly associated with mass transport at the (Cu/SiN[SUBx] cap-layer interface. The threshold product of current density and line length (jL)[SUBc] for Cu/porous MSQ was found to be 2500-3000 A/cm. The reduction in EM lifetime compared with Cu/oxide interconnect can be attributed to smaller back stress, due to less thermo mechanical confinement of Cu/low k interconnects. Most interconnects failed by voiding at the cathode. Some lateral Cu extrusion followed by interfacial breakdown was also observed near the anode. [ABSTRACT FROM AUTHOR]

Electromigration tests at temperatures between 340 and 400 °C and current densities between 1.0 and 3.0 MA/cm[sup 2] have been performed to determine the temperature dependence of the critical length effect in 0.5-μm-wide Cu/oxide dual-damascene interconnects with 0.1 μm silicon nitride (SiN[sub x]) passivation. A focused-ion-beam-induced contrast imaging technique is used to locate failure sites of critical length test structures. Statistical analysis [E. T. Ogawa et al., Appl. Phys. Lett. 78, 18 (2001)] yields a threshold-length product (jL)[sub c], of 3700 A/cm, and a temperature dependence is not observed within the temperature range 340–400 °C. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Electromigration results have provided clear evidence of a short or "Blech" length effect in dual- damascene, Cu/oxide, multilinked interconnects. The test structure incorporates a repeated chain of Blech-type line elements and is amenable to failure analysis tools such as focused ion beam imaging. This large interconnect ensemble provides a statistical representation of electromigrationinduced damage in the regime where steady-state interconnect stress is manifest. Statistical analysis yields a critical length of 90 μm for interconnects with line width 0.5 μm at j=1.0x10[sup 6] A/cm[sup 2] and T=325 °C. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Multi-link statistical test structures were used to study the effect of low k dielectrics on EM reliability of Cu interconnects. Experiments were performed on dual-damascene Cu interconnects integrated with oxide, CVD low k, porous MSQ, and organic polymer ILD. The EM activation energy for Cu structures was found to be between 0.8 and 1.0eV, indicating mass transport dominated by diffusion at the Cu/SiNx cap-layer interface, independent of ILD. Compared with oxide, the decrease in lifetime and (jL)c observed for low-k structures can be attributed to less dielectric confinement in the low k structures. An effective modulus B obtained by finite element analysis was used to account for the dielectric confinement effect on EM and found to correlate well with EM lifetime and the (jL)c product of low-k interconnects. [Copyright &y& Elsevier]

Describes the measurement of the biaxial modulus, coefficient of thermal expansion (CTE) and moisture uptake characteristics of hydrogen silsesquioxane (HSQ) thin films using a bending beam method. Biaxial modulus and CTE of an HSQ film measured on Si and Ge substrates; Value determined for the diffusion constant of water in thick HSQ films at room temperature.