Development of a distributed ferromagnetic enhanced inductively coupled plasma source for plasma processing

Abstract

A low frequency (∼100 kHz) distributed ferromagnetic enhanced inductively coupled plasma (FMICP) source with a separate supply of argon and chlorine into the main discharge chamber is proposed in order to obtain a large volume of dense (1010−1012 cm-3) uniform plasma at low pressures (1−100 mTorr). Argon is activated by FMICP sources in U-shaped tubes and diffuses into the main chamber, mixing with chlorine. The Ar/Cl2 mixture is also activated in the main discharge chamber by vortex alternating electric fields circulating in U-tubes and in the chamber. A separate supply of Ar into the side FMICP sources and Cl2 directly into the main chamber can significantly enhance the power transfer efficiency into the main discharge chamber to be used for plasma etching of 450 mm wafers.

Large-scale ferromagnetic enhanced Ar/Cl2ICP

“…This situation can be improved by increasing the pumping capacity and the argon flow rate, respectively. At high argon flow rates we can expect a decrease of chlorine concentration and electric field strength in the Ushaped tubes, leading to lower values of power consumed by plasma in the U-shaped tubes [32].…”

The effect of chlorine addition on ferromagnetic-enhanced inductively coupled plasma

“…In this case, a minimal value of FMICP resistance is desirable in the U-shaped tube, to minimize the value of absorbed power and hence the value of power losses. To solve this problem, we have proposed using a separate feed of Cl 2 and Ar 31) into the processing chamber and the U-shaped tube, to minimize the U-shaped tube's Cl concentration and the electric field strength respectively. The results on the Ar/Cl 2 FMICP electric field strength dependences obtained in this paper confirm the need for a separate gas supply to solve the problem of U-shaped tube heat loss growth with the addition of Cl 2 .…”