Search

The material properties of two ultra low-k organic polymers are characterized for copper interconnect integration. The k-values are 2.2-2.3 for both. Compared to OSG materials of similar k-values, these polymers have lower porosity and smaller pore size, achieved using selfassembled chemistry. Both materials demonstrate excellent resistance to plasma damage: no water uptake was detected after exposure to selected etching plasmas. This characteristic, combined with the small pore size and low porosity, results in the successful integration of the organic low-ks in 80 nm spacing with no significant increase in the integrated k-values.It is found that higher open porosity in polymer A is accompanied by higher leakage current, which is not however linked to lower dielectric breakdown lifetimes.

We have demonstrated a uniform, robust interface for high-k deposition with significant improvements in device electrical performance compared to conventional surface preparation techniques. The interface was a thin thermal oxide that was grown and then etched back in a controlled manner to the desired thickness. Utilizing this approach, an equivalent oxide thickness (EOT) as low as 0.87 nm has been demonstrated on high-k gate stacks having improved electrical characteristics as compared to more conventionally prepared starting surfaces.

Photoresist removal from silicon substrates has been achieved by a dry processing method using a plasma remote from the substrate to produce active species. Although the principal gas used is oxygen, the addition of small amounts of other gases (N2O, HCI, HBr, H2, Cl2, CF4, and CHF3) has been shown to significantly enhance resist removal. The measured temperature dependences indicate that the effect of these additives may be a combination of oxygen atom production enhancement by neutral and ionic mechanisms as well as independent reaction with the resist.