High-Resolution Piezo Inkjet Printhead Fabricated by Three Dimensional Electrical Connection Method using through Glass VIA

High-resolution piezo inkjet (PIJ) printhead with 1200 nozzles per inch (npi) has been developed. A glass substrate with through holes is bonded to Si substrate with piezo actuators (PAs) placed in matrix array (32 × 16) via polyimide film planarized by grinding method. A thin PA composed of sputter-deposited Pb(Zr, Ti)O
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(PZT) film and Si diaphragm contributes to a shrink of PA size and then high dense integration. The through holes are electroplated with Ni, and Ti/Cu interconnect is formed by resist spray coating and wet etching method. The glass substrate also acts as an encapsulation plate to form a cavity space over the PA, which enables a desirable displacement of the PA. The PIJ printhead exhibited a successful ejection of 2pl ink drops by single jetting drive and 8pl ink drops by three multiple jetting drive.