Cu dual damascene process for 0.13 um technology generation using self ion sputtering (SIS) with ion reflector

Newly developed self ion sputtering(SIS) system is applied to Cu seed formation for electroplating (EP)-Cu filling. SIS is a bias sputtering using Cu⁺ ions generated by self sustained Cu plasma with controlling ion flux to a substrate by an ion reflector. This method can be realized by small modification of long throw sputtering (LTS) configuration. Substrate bias promotes transportation of Cu ions to the bottom of via holes efficiently from Cu plasma, which leads to improve step coverage. However, in the case of only applying substrate bias, uniformity of step coverage across the wafer can not be achieved to the objective value. Ion reflector converges ions on the wafer, especially on the edge of the wafer, then it improves uniformity of step coverage across the wafer. EP-Cu filling of vias of 0.2 um, A/R of 4 can be obtained using this method. Moreover, vias of 0.17 um, A/R of 5 can be completely filled when SIS is applied to barrier metal (TaN) deposition due to drastic improvement of TaN coverage