Planar thin-films of a 60ZrF(4). 35BaF(2). 5PrF(3) composition were successfully prepared from Zr(hfa)(4), Ba(hfa)(2)(tg), Pr(fod)(3) and NF3 by an electron cyclotron resonance plasma-enhanced chemical vapor deposition technique. The films obtained were colorless and amorphous. As etching processing of the prepared thin-film, dry etching was performed using Ar, CF4, SF6, Cl-2 and Cl-2-BCl3 gases. The Ar etching in which no reactive ion-etching is anticipated exhibited the fastest etching rate. Wet etching was also performed using a ZrOCl2-HCl etching solution. The etching rate was extremely fast compared with those of dry etching. In this etching, however, undesirable side-etching occurred. At the present stage, therefore, the most preferable etching processing is dry etching by an Ar gas.