Reactive Ion Etching (RIE)

We are interested in understanding the plasma etching mechanism, which includes plasma phase chemistry, plasma-surface reactions, and surface reactions. We specialize in studying etch processes of non-conventional thin-film materials such as copper, indium tin oxide, metal oxides, a-Si:H, SiNx, and SiGex, for future generations of VLSI, TFT, and other microelectronics or opto-electronics. High temperature RIE is a powerful method that has the advantages of a simple reactor design and being easy to transfer to accommodate large substrates (e.g. 12" for VLSI and 1m x 1m for TFT LCDs). Some examples of recent results are shown as follows. For more detailed information, please see the Publications List.

Plasma-Based Copper Dry Etching Process

- Room Temperature Capability

Vertical Profile:


Y. Kuo and S. Lee. Appl. Phys. Lett. 78(7), 1002-1004, 2001.

S. Lee and Y. Kuo. J. Electrochemical Society. 148(9), G524-529, 2001.

0.8m line:


A 0.8 micrometer Cu line etched by HCl/Ar plasma

Y. Kuo, et al. Proc. ISSP 2003, p. 305-308. and Vac. 2004


- Exposure Time

HCl Exposed Cu

Cu RIE added Slide2

S. Lee and Y. Kuo, Thin Solid Films, 2003.

- No Plasma vs. Plasma

HCl Exposed Cu no plasma

HCl Plasma Exposed Cu

S. Lee and Y. Kuo, JJAP 41, 1(12), 2003.

- Structure

CuBrx from HBr Plasma Exposure

Cu RIE added Slide3

S. Lee and Y. Kuo, Thin Solid Films, 2003.

Cu RIE added Slide4

S. Lee and Y. Kuo, JJAP 41, 1(12), 2002.

- Mechanism

Novel Dry Etching of Copper for ULSI Interconnection


Y. Kuo & S. Lee, Jpn. J. Appl. Phys. 39, 2(3A/B), L801, 2000.

APL CuCl before & after stripping

Y. Kuo & S. Lee, APL 78(7), 1002, 2001.


Y. Kuo and S. Lee, ECS Proc. 99-30, 328, 1999.

RIE of Indium Tin Oxide (ITO)

- Non-Additive Feed Gas Effect and Loading Factors

Y. Kuo, Jpn. J. Appl. Phys, 36, 2(5B), L629-L631, 1997.

HBr Etched

HBr/CH4 (60%) Etched

Y. Kuo, ECS Plasma Processing Symp. Proc. XII, 1998.

Surface Reactions

Y. Kuo and T. L. Tai, JECS, 1998 

Temperature Effect

Y. Kuo, JJAP, 36(2), 5B, L629, 1997

Modification of Patterned Photoresist

hydrogeantion of photoresist

Hydrogenated photoresist is more resistant to plasma etching

Y. Kuo, APL, 2 (1A1B), L 126, 1993.


Plasma Damages to Transistors


Y. Kuo, APL, 61(23), 2790, 1992

Profile Control

Etch Rate Ratio R

RIE Etched Sloped Molybdenum

Y. Kuo, et. al., J. Vac. Sci. Technology, A8(2), 1529, 1998.

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