Suppression of aluminum hillock growth by overlayers of silicon dioxide chemically-vapor-deposited at low temperature

Learn, Arthur J.

doi:10.1116/1.583567

Cited by 9 publications

(1 citation statement)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This method is very effective for vertical hillocks but not for lateral extrusion. Learn 8 proposed decreasing the chemical vapor deposition ͑CVD͒ temperature of ILD films to control the hillock and extrusion growth. But reduction of deposition temperature may compromise ILD quality.…”

Section: Introductionmentioning

confidence: 99%

Influence of underlying interlevel dielectric films on extrusion formation in aluminum interconnects

Chen

Sullivan

et al. 2000

Journal of Vacuum Science &Amp; Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena

View full text Add to dashboard Cite

Effect of low-energy N 2 + ion beam bombardment on silicate glass thin films studied by x-ray photoelectron spectroscopy Knowledge of the mechanical properties of interlevel dielectric films and their impact on submicron interconnect reliability is becoming more and more important as critical dimensions in ultralarge scale integrated circuits are scaled down. For example, lateral aluminum ͑Al͒ extrusions into spaces between metal lines, which become more of a concern as the pitches shrink, appear to depend partially on properties of SiO 2 underlayers. In this article nanoindentation, wafer curvature, and infrared absorbance techniques have been used to study the mechanical properties of several common interlevel dielectric SiO 2 films such as undoped silica glass using a silane (SiH 4 ) precursor, undoped silica glass using a tetraethylorthosilicate precursor, phosphosilicate glass deposited by plasma-enhanced chemical vapor deposition and borophosphosilicate glass ͑BPSG͒ deposited by subatmosphere chemical vapor deposition. The elastic modulus E and hardness H of the as-deposited and densified SiO 2 layers are measured by nanoindentation. The coefficients of thermal expansion ͑CTE͒ of the densified layers are estimated by temperature-dependent wafer curvature measurements. Fourier transform infrared spectroscopy is used to obtain the chemical structures of all SiO 2 layers. Among the four common interlevel layers, BPSG exhibits the smallest modulus/ hardness and a relatively small amount of moisture loss during anneal. The BPSG shows the highest CTE, which generates the smallest thermal stress due to a closer match in the CTE between Al and SiO 2 . BPSG again has the lowest as-deposited compressive stress and the lowest local Si-O-Si strain before annealing. The center frequency of the Si-O bond stretching vibration exhibits a linear dependence on total film stress. The shifts of Si-O peaks for all the SiO 2 layers also correlate well with the stress hysteresis obtained from wafer curvature measurements. Stress interactions between the various SiO 2 underlayers and the Al metal film are also investigated. The impact of dielectric elastic properties on interconnect reliability during thermal cycles is proposed.

show abstract

Section: Introductionmentioning

confidence: 99%