Producing surface grid structure with phase change for DFB-laser - uses soluble plastic auxiliary layer in process step requiring no etching

摘要

A positive photoresist is applied to a substrate surface and a phase jump-free grid structure produced. A plastic auxiliary layer is then applied, and a second photoresist layer applied. Part of this is removed, and the bare plastic layer is removed. A metal layer is applied, and the photoresist of the bore resist mask and the metal layer over it removed. The remaining part forms the grid with phase jump. The second to photoresist layer is pref. a negative photoresist. Pref. the plastic is water soluble, e.g. a polyvinyl alcohol. Titanium may be used for the metal layer. ADVANTAGE - Only one metal-active etchant needed.