IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Plasma Science Thursday Sessions
       Session PS-ThP

Paper PS-ThP33
Effects of Gas Chemistry of Inductively Coupled Plasmas on the Multi-Layer Gate Metal Etching Characteristics for TFT-LCD Devices

Thursday, November 1, 2001, 5:30 pm, Room 134/135

Session: Plasma Etching Poster Session
Presenter: Y.J. Lee, Sungkyunkwan University, Korea
Authors: Y.J. Lee, Sungkyunkwan University, Korea
C.H. Yi, Sungkyunkwan University, Korea
B.K. Song, Sungkyunkwan University, Korea
M.J. Chung, Sungkyunkwan University, Korea
M.P. Hong, Samsung Semiconductors, Korea
G.Y. Yeom, Sungkyunkwan University, Korea
Correspondent: Click to Email
For advanced TFT-LCD manufacturing processes more conductive gate materials are required for the next generation large size and the high quality of thin film transistor liquid crystal displays (TFT-LCDs). For gate metal layer, single gate metals such as Al-Nd and Ag, and double gate metals such as Al-(Cr, Mo, MoW, or W) are widely studied. Currently, the patterning of gate metals is done by wet etching methods. With the wet etching method, however, the tapered patterning of Al-alloy mentioned above is nearly impossible. Also, most of the capacitively coupled RIE-type equipments available for FPD devices are suffered from relatively low plasma densities, therefore, low etch rates. Therefore, in this study, the tapered etching of multi-layer gate metals such as Ag, Al-Nd, and double gate metal films (Al-Cr, Mo, W, or MoW) deposited on glass substrates were studied using high density inductively coupled plasmas (ICP) and the etch characteristics were investigated as a function of gas combination, pressure, dc self-bias voltage, and inductive power. Chlorine and bromine-based gas were used with N@SUB 2@, O@SUB 2@, and Ar as additive functional gases. Depending on the materials, the different etch rates were obtained for the same process parameter condition. For example, the etch rates close to 1500Å/min could be obtained using BCl@SUB 3@/HBr chemistry for Al-Nd etching and the etch selectivity over photoresist was close to 1. The low etch rates were attributed to the Nd in Al. Using the plasma diagnostic tools such as optical emission spectroscopy and quadruple mass spectroscopy, the etching mechanisms of various gate metal layers with these chemistries were investigated. Variations of surface composition for various gas mixtures were also investigated using X-ray photoelectron spectroscopy. The etch profiles and surface defects were observed with a scanning electron microscope.