| 摘要 |
PURPOSE:To change an elastic surface-wave element into high frequency and improve its performance by forming an electrode on an Li2B4O7 crystalline substrate through a photoetching method without damaging the substrate. CONSTITUTION:The surface of the Li2B4O7 crystalline substrate 1 mirror-ground is coated with an Al film 2 in 1mum thickness. A substance such as OMR45CP is rotary-applied as a negative type resist 3, and pre-baked for thirty min at 150 deg.C. A photo-mask 4 to which an inversion image of an electrode pattern is written is fast stuck on the substrate, and ultraviolet rays 5 are irradiated for three or five sec to expose the photo-mask. The exposed substrate is rinsed and developed to form a resist pattern, the substrate is agitated for five or eight min in a 5wt% KOH aqueous solution, and the unnecessary Al film is removed to form the interdigital electrode. Lastly, the resist 3 is removed by holding the substrate in oxygen plasma for ten or twenty min. Accordingly, the substrate to which the electrode is formed is divided into several device, and the devices are encased in vessels and formed. |
