Two-Step Process for Etching Printheads
Original Publication Date: 1987-Jan-01
Included in the Prior Art Database: 2005-Jan-31
Using a double-sided chemical wet etch as the first step, and then using a single sided wet etch as the final step, is an effective process for making thermal printheads with wide electrodes. Fig. 1 shows etched trenches 1 in tungsten sheet 2 after the double-sided etch. The process starts with bare tungsten. Double- sided etching is done for the electrodes. First, the bare tungsten is dipped into photoresist, and then both faces are exposed with the wide electrode pattern. This is done in one step using a double-sided mask aligner. A double-sided wet spray etch is done. After the etching, the sheet of tungsten has many sets of electrodes etched in it. The resist is removed from both sides. Fig. 2 shows the resist pattern prior to the single-sided etch.