Study of FSG/SiO/sub 2/ double interlayer conditions to prevent Al wiring delamination for sub-0.18-μm device integration

Abstract

A double interlayer of high-density plasma fluorinated silica glass (FSG) and SiO 2 has been developed to control fluorine instability for sub-0.18-m devices. However, the interlayer conditions need further study for robust integration. The authors investigate the optimum conditions to prevent Al wiring delamination. The correlation between the incidence of delamination and F concentration at Ti-SiO 2 was demonstrated by the three-dimensional mapping of interfacial F concentrations with various thicknesses of SiO 2 and F contents in FSG. Detailed analysis of the Ti-SiO 2 interface reveals that the anomalous growth of the interface layer by absorbing F atoms into the Ti layer causes delamination. The properties of SiO 2 , such as the compressive stress and the density of oxygen deficiency, were adjusted to reduce F diffusion. In addition, the thickness was controlled to above 4500 Å to suppress F accumulation at Ti-SiO 2 to within the permissible level. In contrast, the F content in the FSG film was used at 4.4 at.% since the interfacial F concentration was independent of the F content in the range of 2-5 at.%. These conditions resulted in preventing delamination and obtaining integration reliability without increasing the capacitance between adjacent metal lines.Index Terms-Fluorinated silica glass, high-density plasma, intermetal dielectric, metal delamination.

Effect of deposition temperature on thermal stability in high-density plasma chemical vapor deposition fluorine-doped silicon dioxide

“…This type of defect was found on the metal pads, shown in Fig. 7͑a͒, similar to the result of Kawashima et al 14 derlayer barrier layer ͑TiN͒, metal lines ͑Al͒, and passivation layer (Si 3 N 4 ). Another defect type, i.e., peeling, is also observed for a 350°C SiOF film, as shown in Fig.…”

Optimization of post-N2 treatment and undoped-Si-glass cap to improve metal wring delamination in deep submicron high-density plasma-fluorinated silica glass intermetal dielectric application

“…5-3.8), high gap-filling capability, and especially simplicity of IMD integration. 8,9 Several methods have been proposed to prevent the metal delamination. %, induces water absorption and degrades film properties.…”

“…3,4 However, high fluorine concentration of the FSG films, exceeding 5 at. 4,8,10 However, the effect of process conditions of N 2 treatment and capping layers on the metal delamination is not fully examined in previous studies. [5][6][7] Moreover, fluorine outgassing results in metal delamination due to the degradation of adhesion ability.…”