CONTROLLED INK-JET PRINTING AND DEPOSITION OF ORGANIC POLYMERS AND SOLID PARTICLES

In this letter, we present a technique for the deposition of inks, org anic polymers and solid particles, using a fluid ejector. The ejector design is based on a flextensional transducer that excites axisymmetri c resonant modes in a clamped circular membrane. It is constructed by bonding a thin piezoelectric annular ring to a thin, edge supported, c ircular membrane. Liquids or solid particles are placed behind one fac e of the membrane which has a small orifice (50-200 mu m diam) at its center. mm By applying an ac signal across the piezoelectric element, continuous or drop-on-demand ejection of photoresist (Shipley Micropos it S1400-21, S1400-27, S1805, and S1813), oil-based ink, water, or tal cum powder [Mg3Si4O10(OH)(2)] has been achieved. Successful deposition of photoresist has been accomplished without spinning, and thus witho ut waste. Patterning of 10 mu m features, by baking, exposure, and dev eloping, has revealed no defects in the deposition process. A boundary integral method was used to numerically simulate drop formation from the vibrating orifice. Simulations have been used to optimize ejection performance. (C) 1998 American Institute of Physics. [S0003-6951(98)0 1442-9].