No abstract

The characteristics of a line-type, internal antenna for an inductively coupled plasma (ICP) source installed with a ferromagnetic module were investigated for possible application to roll-to-roll processing of next-generation display devices. The use of 2 MHz instead of 13.56 MHz for the 2300 mm long ICP source improved the plasma uniformity to less than 11% along the antenna line. In addition, the use of Ni-Zn ferromagnetic material in the line-type antenna improved the plasma density to about 3.1 × 10 11 cm −3 at 3500 W of 2 MHz radio frequency power by confining the induced, time-varying magnetic field between the antenna line and the substrate. When the photoresist-covered glass substrate was etched at 4000 W using 40 mTorr and Ar/O 2 (7 : 3), an etch uniformity of about 5-6% was obtained along the antenna line.

The effect of C-shaped ferrite modules installed above a spiral-type inductively coupled plasma (ICP) antenna coil and the plasma characteristics of an ICP source operated at 2 MHz were investigated in order to realize 450 mm wafer processing. The application of an appropriate amount of Ni-Zn ferrite modules to the antenna increased the plasma density slightly and decreased the plasma potential, while the application of the ferrite modules all over the antenna line decreased the plasma density and increased the plasma potential. In particular, by installing the ferrite modules locally in a low-plasma-density region, plasma uniformity was improved effectively.

An internal-type linear inductive antenna, which is referred to as ''double comb-type antenna'', was used as a large-area inductively coupled plasma (ICP) source with a substrate area of 2,300 mm 9 2,000 mm. The characteristics of the ICP source were investigated for potential applications to flat panel display (FPD) processing. The source showed higher power transfer efficiency at higher RF power and higher operating pressures. The power transfer efficiency was approximately 88.1% at 9 kW of RF power and a pressure of 20 mTorr Ar. This source showed increasing plasma density and improved plasma uniformity with increasing RF power at a given operating pressure. A plasma density [1.5 9 10 11 /cm 3 and a plasma uniformity of approximately 11% was obtained at 9 kW of RF power and 15 mTor Ar using this internal ICP source, which is applicable to FPD processing.

Silicon-on-insulator (SOI) wafers were etched by an energetic chlorine neutral beam obtained by the low-angle forward reflection of an ion beam, and the surface roughness of the etched wafers was compared with that of the SOI wafers etched by an energetic chlorine ion beam. When the ion beam was used to etch the silicon layer of the SOI wafers, the surface roughness was not significantly changed even though the use of higher ion bombardment energy slightly decreased the surface roughness of the SOI wafer. However, when the chlorine neutral beam was used instead of the chlorine ion beam having a similar beam energy, the surface roughness of the SOI wafer was significantly improved compared with that etched by the chlorine ion beam. By etching about 150 nm silicon from the SOI wafer having a 300 nm-thick top silicon layer with the chlorine neutral beam at the energy of 500 eV, the rms surface roughness of 1.5 Å could be obtained with the etch rate of about 750 Å min −1 .