AVS 57th International Symposium & Exhibition
    Plasma Science and Technology Thursday Sessions
       Session PS-ThP

Paper PS-ThP17
Atmospheric Pressure Plasma Ashing of Photoresist using Remote-type Pin-To-Plate Dielectric Barrier Discharge

Thursday, October 21, 2010, 6:00 pm, Room Southwest Exhibit Hall

Session: Plasma Science and Technology Poster Session
Presenter: J.S. Oh, Sungkyunkwan University, Republic of Korea
Authors: J.S. Oh, Sungkyunkwan University, Republic of Korea
J.B. Park, Sungkyunkwan University, Republic of Korea
E.L. Gil, Sungkyunkwan University, Republic of Korea
G.Y. Yeom, Sungkyunkwan University, Republic of Korea
Correspondent: Click to Email

In these days, many researchers are developing glow discharges generated at atmospheric pressure for various thin films and surface processing such as dielectric barrier discharge (DBD), microwave discharge, pulsed corona plasma, etc. Various atmospheric pressure plasma sources have been reported with the claim of low running cost, low gas temperature, and wide applicability to surface treatment, cleaning, etching, and thin film deposition. Among the various atmospheric pressure plasmas, DBDs are studied mostly due to the easy generation of stable plasma.

In this study, ashing of photoresist (PR), AZ 1512, has been investigated using a pin-to-plate remote type DBD. The pin-to-plate type DBD showed higher power consumption and higher discharge current compared to the conventional DBDs at a given applied voltage. But glow discharge, which is generated by DBD, is easily transferred to filamentary/arc discharge, and the substrate is more likely to be damaged under arc discharge condition. Also, thermal damage can occur due to direct contact of the plasma to the substrate. But, remote plasma does not contact the substrate directly, therefore, the substrate can avoid damaging. In this study, using the remote type pin-to-plate DBD, the effect of various gas combinations such as N2/O2, N2/O2+SF6 on the changes of PR etch rate and the electrical characteristics was investigated.

The addition of SF6 gas to N2/O2 showed higher consumed power, higher discharge current at a given voltage, and lower turn-on voltage. For example, the plasma turn-on voltage for N2 (50 slm)/O2 (200 sccm) was 3.16 kV while that for N2 (50 slm)/O2 (200 sccm)/SF6 (2.5 slm) was 2.7 kV, therefore, a lower turn-on voltage was obtained by adding 2.5 slm of SF6. The consumed power for N2 (50 slm)/O2 (200 sccm)/SF6 (2.5 slm) was 2330 W while that for N2 (50 slm)/O2 (200 sccm) was 1119 W. Therefore, the addition of 2.5 slm of SF6 increased the power consumption in the plasma by ionizing and dissociation the gas mixture further possibly through the penning ionization and dissociation. At N2 (70 slm)/ O2 (200 sccm) + SF6 (3 slm), the maximum PR etch rate of about 1850 nm/min could be achieved.