New reflowable organic spin‐on glass for advanced interlevel dielectric planarization

New reflowable organic spin-on glass (SOG) was developed to form planarized multilevel interconnections for ULSIs. This SOG had superior gap-filling and plan-arizing characteristics compared to those of conventional organic SOGs. For example, using this SOG, a 0.025-μm wide trench with an aspect ratio of over 10 could be perfectly filled without void. The surface of a three-layered interlevel dielectric structure with this SOG was four times smoother than that with a conventional organic SOG. It was found that the excellent gap-filling planar-izing property of this SOG was due to the low temperature reflow (100 to 200°C). The film quality was almost the same as that of an organic SOG which has been widely used and has exhibited sufficient reliability. That is, this organic SOG gives a sufficient reliability with far improved gap-filling and planarization. Since the relative dielectric constant of this SOG is as low as 3.0, this SOG is promising to improve the operation speed of ULSI.