Plasma and impedance characteristics of internal linear antennas for flat panel display applications

The trend towards large area substrates motivated by flat panel display industries has accelerated the development of the large size plasma sources. In this study, two types of linear internal-type inductively coupled plasma source enabling the production of large area high density plasma, that is, a serpentine-type and a double comb-type were investigated and their characteristics of plasma and impedance were compared. The use of the double comb-type antenna showed higher root-mean-square current, higher plasma density, and lower antenna resistance compared to that of the serpentine-type antenna as the rf power increased from 600 to 5000 W. By the application of 5000 W of rf power with 2 Pa Ar, a high plasma density of 2.2 × 1011/cm3 with the plasma uniformity of 8% for the size of 880 × 680 mm could be obtained for the double comb-type antenna. The improved characteristics of the double comb-type antenna compared with the serpentine-type antenna appear to be from the higher inductive coupling and less standing wave effect compared to the serpentine-type antenna.