The fabrication of aluminium structures generally involves the production of a resist mask with subsequent wet-chemical etching. The more elegant procedure of direct development can be applied if the negative resist SX AR-N 4360/1 is used for this purpose. This photoresist with exceptionally high resistance against alkaline developers is directly spin-deposited onto the aluminium, followed by the usual bake, exposure and development steps. As developer, the concentrated metal ion-free developer AR 300-44 is used. After a removal of exposed photoresist layers, the developer attacks the now accessible areas of the aluminium. Aluminium films with a thickness of 100-nm are removed within two minutes. After the resist mask is removed in a simple procedure, the desired aluminium structures remain.
Overview General Process