Forming conductive vias using a light guide

A process comprising:

• providing a via in a base material, comprising at least two copper lines and at least one insulator layer separating the at least two copper lines, in a direction perpendicular to a plane of the base material,
• wherein the via intersects the at least two copper lines;
• applying a photoresist layer to an interior surface of the via;
• inserting a light guide into the via,
• wherein a portion of an outer surface of the light guide is masked;
• exposing, via the light guide, a portion of the photoresist layer to light, thereby resulting in an exposed portion of the photoresist layer and an unexposed portion of the photoresist layer;
• and
• removing a portion of the photoresist layer.

A process comprising:

• providing a via in a base material, comprising at least two copper lines and at least one insulator layer separating the at least two copper lines, in a direction perpendicular to a plane of the base material,
• wherein the via intersects the at least two copper lines;
• applying a photoresist layer to an interior surface of the via;
• inserting a light guide into the via;
• exposing, via the light guide, a portion of the photoresist layer to light, thereby resulting in an exposed portion of the photoresist layer and an unexposed portion of the photoresist layer;
• and
• removing a portion of the photoresist layer.