Method for pattern-etching alumina layers and products

A process for pattern-etching an alumina layer, the process comprising:

• forming an alumina layer over a substrate;
• depositing at least one metallic layer over said alumina layer, said at least one metallic layer comprising a bottom adhesion metallic layer and a top metallic layer, said top metallic layer and said bottom adhesion metallic layer are the same metallic layer when said at least one metallic layer comprises a single metallic layer;
• forming a photoresist mask over said top metallic layer, said photoresist mask having formed therethrough at least one opening exposing the top metallic layer;
• forming a metallic mask by removing a portion of said top metallic layer exposed through the at least one opening in said photoresist mask, thereby forming at least one opening in said top metallic layer, and by removing a portion of other underlying metallic layers, if any, through the at least one opening in said top metallic layer, thereby forming at least one opening in said metallic mask exposing the alumina layer;
• and
• etching at least a portion of said alumina layer exposed through said at least one opening in said metallic mask by applying a wet alumina etchant to pattern-etch said alumina layer, said wet alumina etchant comprising HF, said at least one metallic layer being substantially free of pores and substantially immune from etching by said wet alumina etchant, and said photoresist mask is removed prior to the step of etching the at least a portion of the alumina layer.

A process for pattern-etching an alumina layer, the process comprising:

• forming an alumina layer over a substrate;
• depositing a bottom adhesion metallic layer over the alumina layer;
• depositing at least one additional metallic layer, one of which at least one additional metallic layer is a top metallic layer, over the bottom adhesion metallic layer;
• forming a photoresist mask over the top metallic layer;
• etching the top metallic layer through the photoresist mask;
• etching through the top metallic layer, in reverse order of deposition, all other metallic layers;
• wet etching the alumina layer with a wet alumina etchant through all metallic layers;
• and
• removing all the metallic layers.

A process for pattern-etching an alumina layer, the process comprising:

• depositing an alumina layer on a substrate;
• depositing on the alumina layer one or more metallic layers which include a bottom adhesion metallic layer;
• forming a photoresist layer over the one or more metallic layers;
• forming a photoresist mask by forming at least one opening through the photoresist layer to expose a portion of said one or more metallic layers, said at least one opening defining the location of at least one crater;
• removing a portion of said one or more metallic layers through the at least one opening in the photoresist layer to form at least one opening in the one or more metallic layers thereby exposing the underlying alumina layer;
• etching the alumina layer through the at least one opening in the adhesion metallic layer with a wet alumina etchant, wherein at least one of said one or more metallic layers is substantially free of pores and substantially immune from etching by said wet alumina etchant;
• removing the photoresist mask;
• and
• removing the one or more metallic layers.

A process for pattern-etching an alumina layer, the process comprising:

• depositing an alumina layer over a substrate;
• depositing over the alumina layer a first mask comprising at least one metallic layer, said at least one metallic layer comprising a bottom adhesion metallic layer and a top metallic layer, said top metallic layer and said bottom adhesion metallic layer are the same metallic layer when said at least one metallic layer comprises a single metallic layer;
• forming a photoresist mask having at least one opening over the top metallic layer exposing the top metallic layer;
• pattern-etching at least one opening in the first mask to expose a surface of the alumina layer by etching a portion of the top metallic layer through the at least one opening in the photoresist mask and removing a portion of other underlying metallic layers, if any, through the at least one opening in said top metallic layer;
• and
• pattern-etching the alumina layer with a wet alumina etchant comprising HF through the at least one opening in the first mask, wherein the first mask is substantially free of pores and substantially immune against attack by the alumina etchant.

A process for pattern-etching an alumina layer, the process comprising:

• forming an alumina layer over a substrate;
• forming a mask over said alumina layer, said mask comprising at least one metallic layer, said at least one metallic layer comprising a bottom adhesion metallic layer and a top metallic layer, said top metallic layer and said bottom adhesion metallic layer are the same metallic layer when said at least one metallic layer comprises a single metallic layer, said mask having formed therethrough at least one opening;
• and
• etching at least a portion of said alumina layer by solely applying a wet alumina etchant, comprising HF, through said at least one opening to pattern-etch said alumina layer, said at least one metallic layer being substantially free of pores and substantially immune from etching by said wet alumina etchant, said step of forming a mask comprises:
• forming a photoresist layer over said top metallic layer;
• forming at least one opening through said photoresist layer to expose a portion of said top metallic layer;
• and
• removing a portion of said top metallic layer exposed through the at least one opening in said photoresist layer and removing a portion of other underlying metallic layers, if any, through the at least one opening in said top metallic layer.