Fluorinated amorphous carbon thin films (a-C:F) for use as low-dielectric-constant interlayer dielectrics were deposited by helicon-wave plasma-enhanced chemical vapor deposition using fluorocarbon compounds as a source material. The a-C:F films could be grown from C4F8 at a high deposition rate (above 400 nm/min) and they were thermally stable up to 300°C. The addition of bias power to the substrate made it possible to completely fill gaps in the wiring (space 0.35 μm, height 0.65 μm) with the a-C:F film. To protect the a-C:F film during further processing, we deposited a SiO2 film to add mechanical strength and resistance to the oxygen plasma used to remove resist materials. The adhesion between the a-C:F and SiO2 films was dramatically improved by inserting an adhesion promoter consisting of a-C:H and Si-rich SiO2.

Poly(arylene ethers)s are low dielectric constant organic spin on materials. PAE-2, which is a non-fluorinated poly(arylene ether), exhibits a dielectric constant below 3.0, thermal stability greater than 425 °C as well as excellent adhesion to Si, SiO2, and Al. These are the major atributes which makes it a very attractive candidate for integration as an interlevel or inter-metal dielectric material (ILD). Material properties including dielectric constant, thermal stability, moisture absorption, and mechanical analysis will be discussed.

Three low dielectric constant organic polymers are being investigated for possible use in a conventional, subtractive etch, multi-level metal process with PVD Al plugs. Material properties, physical properties, planarization ability and etch chemistries are compared, as well as the possibility of using these materials in a low temperature PVD A1 plug process.

Fluorinated high-density plasma and plasma-enhanced CVD SiO2 inter-metal dielectrics have been evaluated for 0.50- through 0.25- μm generation CMOS. Several integration issues are discussed, including the impact of fluorine-doped SiO2 on the yield, reliability, and RC delay of 0.7 - 1.8 μm pitch back-end-of-the-line AlCu/tungsten-stud wiring.

Pulsed-rf excitation of hexafluoropropylene oxide (HFPO) has been used to deposit films with chemical compositions similar to poly(tetrafluoroethylene) (PTFE). Films were deposited at pulse cycles of 10/20, 10/50, 10/200, and 10/400 ms on/ms off and analyzed using electron spin resonance spectroscopy (ESR). All four films produced similar broad ESR spectra, with an average width at maximum slope of ˜60 G and a g-value of 2.0045. The concentration of free electrons in a sample decreased with increasing pulse off time. This behavior can be modeled by the reaction of a free radical with a gas species, assuming that free radicals are generated only during the pulse on time. The films' dielectric constants were found to decrease from 1.99 to 1.95 for pulse off times increasing from 20 to 400 ms.

Hydrogen silsesquioxane spin-on-glass (SOG) is regarded as a potential low-k material for multilevel metallization (MLM) schemes. In this work we report on the properties of films which have been cured at different temperatures covering the range from 350°C to 850°C. It is found that the material remains in its microporous structures at the lower temperature while it can be strongly densified at increased thermal budgets. The slope of the dielectric constant indicates that care ought to be taken in subsequent metallization anneals in order to preserve the low-k values observed.