Large-area uniform material processing is demonstrated in reactive plasmas produced by a plane antenna with permanent magnets for the electron-cyclotron resonance at 2.45 GHz. Oxygen (O2) plasmas are used for the ashing of photoresist films; sulphur hexafluoride (SF6) and carbon tetrafluoride (CF4) are used for the etching of polysilicon and silicon dioxide films, respectively. In both cases the plasma parameters are measured in detail. Typically, the electron density in O2 and CF4 plasmas is about (1-2)×1010 cm-3 and the electron temperature is about 3 eV for a microwave power of 600 W. However, ne ≃ 109 cm-3 in the SF6 plasma. The ashing and etching rates for photoresist and polysilicon are 40-50 nm min-1 and the etching rate of silicon dioxide is about 10 nm min-1 in the uniform plasma region (z = 25-35 cm), when the microwave power is 600 W under the condition of the floating substrate potential. A quite homogeneous material processing of those films is established over a diameter of 40-45 cm at the distance of 25-35 cm from the antenna.
ASJC Scopus subject areas
- Condensed Matter Physics