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. Novel chemistry is critical in accomplishing some works that were though impossible to achieve, such as the room temperature plasma etching of copper. 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

                                Process:

-    Exposure Time

HCl Exposed Cu

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

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

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.

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

       

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

-    Sidewall Attack

Cl2 plasma + HCl solution dip

Cl2/CF4 (20%) plasma + HCl solution dip

G. Liu and Y. Kuo, JES 2008.

-         TiW Barrier Layer Etch

(c) Cl 2p3/2,1/2 peaks after CF4(50%)/Cl2 and Cl2 plasma exposure, and (d) F 1s peaks after CF4 and CF4(50%)/Cl2 plasma exposure.

 

G. Liu and Y. Kuo, JES 154(7) H653 (2007).

 

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

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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