Fabrication of a stainless steel shadow mask using batch mode micro-EDM

A metal shadow mask for organic thin-film transistors (OTFTs) has been fabricated by batch mode electro-discharge machining (EDM). Batch mode micro-electro-discharge machining method was applied for productivity improvement. Negative electrode with multiple holes (3 × 3 or 4 × 4) was fabricated using a single tool electrode. With the negative electrode, 3 × 3 and 4 × 4 tool electrode arrays are EDMed; 6 × 6 and 16 × 16 square hole array masks were batch mode EDMed with the fabricated multi-electrodes arrays. With 4 × 4 electrode array, the productivity is improved to five times of that in the case using a single electrode. Source and drain electrodes of OTFTs were successfully patterned on a pentacene active layer through the mask, and the fabricated pentacene TFTs had good output characteristics.