AVS 60th International Symposium and Exhibition
    Plasma Science and Technology Tuesday Sessions
       Session PS-TuP

Paper PS-TuP26
High Etching Rate of Lithium Niobate Substrate using BCl3/Ar Mixture Gases by ICP-RIE

Tuesday, October 29, 2013, 6:00 pm, Room Hall B

Session: Plasma Science and Technology Poster Session
Presenter: M.H. Shiao, National Applied Research Laboratories, Taiwan, Republic of China
Authors: C.M. Chang, National Applied Research Laboratories, Taiwan, Republic of China
P.L. Chen, National Applied Research Laboratories, Taiwan, Republic of China
J. Su, National Applied Research Laboratories, Taiwan, Republic of China
M.H. Shiao, National Applied Research Laboratories, Taiwan, Republic of China
C.-N. Hsiao, National Applied Research Laboratories, Taiwan, Republic of China
Correspondent: Click to Email
In this study, Z-cut LiNbO3 single crystal wafers were etched by the inductively coupled plasma reactive ion etching (ICP-RIE) technique by using the boron trichloride (BCl3)/ Argon (Ar) mixture gases. Effects of the ICP power and RF power ranged from 100W to 400W of the ICP-RIE system were studied on the etching rate, surface roughness, and corresponding DC bias under two working pressures of 30 mTorr and 50 mTorr, respectively. Besides, photoresist and metallic nickel thin film were used as the etching mask, and the selective ratios of the two etching masks were also compared. From the experimental results, it can be found that the DC bias (-V) decreases with the working pressure, and increases with the ICP power and the RF power. The surface roughness of the etched LiNbO3 substrate was decreased from 55 nm to 30 nm with increasing working pressure, but it increased when the ICP power and RF power were increased. The etching rate of the LiNbO3 substrate was increased with increasing the ICP power and RF power under the two working pressure. It is noted that the etching rate was greater than 100 nm/ min when the working pressure was controlled at 30 mTorr. The selective ratios of the photoresist and the nickel were calculated to be approximately 0.4 and 8, respectively. Under suitable processing parameters of ICP-RIE, the surface roughness less than 40 nm, structure depth greater than 2 μm, and sidewall angle greater than 70°°of the LiNbO3 substrate can be obtained within 20 min, which etching rate is greater than 80 nm/ min.