Etching ITO glass

1. Hydrochloric acid wet etching

Shipley S1813 positive photoresist
500rpm/10s
1500rpm/30s
soft bake 110degC 1 min
Exposure using maskless lithography at h-line (405nm) at  250mJ/cm^2
develop in 2.38% TMAH
Post exposure bake 115degC 5min (important for chemical resistance)
etching in IS-2 ITO etching solution containing hydrochloric acid and aluminum nitrate from sasaki chemical co ltd. (Kyoto, Japan)
16 hours. or overnight.

here you can see an long electrode being etched on ITO glass. the Etched ITO pattern is visible under optical microscope due to difference of refractive index.
However, both are optically transparent so the entire view field is unobstructed.

In case of real world application when object of interest are usually not directly on the ITO, the ITO pattern are barely visible.




2. Q-switched green laser etching

The ITO can also be etched by Q-switched green lasers. 

Ji-Yen Cheng, RCAS, Academia Sinica Taiwan

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