OPTIMIZATION OF ETCHING PARAMETERS OF A FLUORINATED POLYIMIDE USING THE RIBE TECHNIQUE

A parametric study of etching a new type of fluorinated polyimide (6FD A-ODA) has been carried out. This kind of material was especially elab orated for plasma etching (reactive ion etching, RIE); its behaviour w as tested with the reactive ion beam etching (RIBE) technique which us es an (O+) reactive ion beam and allows independent control of the ion energy and current density of the beam. Etch rates were measured as a function of energy (E), current density (J) and incident angle (theta ) of the beam with the sample normal. These rates were shown to presen t a maximum value (1000 Angstrom min(-1)) for an energy flux of about 3 W cm(-2) (E = 6 keV and J = 0.5 mA cm(-2)) and decreased when theta increased. These results were then compared with etching rates obtaine d with chemically inert ions (Ar+): in this case, etching rates were f ive times lower than those measured with O+ ions. (C) 1998 Society of Chemical Industry.