Techniques for low- or zero-misaligned vias are disclosed. In one embodiment, a high-photosensitivity, medium-photosensitivity, and low-photosensitivity layer are applied to a substrate and exposed at the same time with use of a multi-tone mask. After being developed, one layer forms a mold for a first via, one layer forms a mold for a conductive trace and a second via, and one layer forms an overhang over the position for the second via. The molds formed by the photosensitive layers are filled with copper and then etched. The overhang prevents the top of the copper infill below the overhang region from being etched. As such, the region under the overhang forms a pillar or column after etching, which can be used as a via. Other embodiments are disclosed.

Techniques that can assist with fabricating a package layer that includes a plurality of dual-damascene zero-misalignment-vias (dual-damascene ZMVs) and a trace between the dual-damascene ZMVs are described. The disclosed techniques allow for the dual-damascene ZMVs and their corresponding trace to be plated simultaneously in a single step or operation. As such, there is little or no misalignment between the dual-damascene ZMVs, the trace, and the metal pads connected to the ZMVs. In this way, one or more of the embodiments described herein can assist with reducing manufacturing costs, reducing development time of fabricating a package layer, and with increasing the I/O density in a semiconductor package.

A method of forming a semiconductor device having a vertical metal line interconnect (via) fully aligned to a first direction of a first interconnect layer and a second direction of a second interconnect layer in a selective recess region by forming a plurality of metal lines in a first dielectric layer; and recessing in a recess region first portions of the plurality of metal lines such that top surfaces of the first portions of the plurality of metal lines are below a top surface of the first dielectric layer; wherein a non-recess region includes second portions of the plurality of metal lines that are outside the recess region.

A substrate having thereon a first dielectric layer, a second dielectric layer, and a hard mask layer is provided. A partial via is formed in the second dielectric layer and the hard mask layer. A first photoresist pattern with a first trench opening above the partial via and a second trench opening is formed on the hard mask layer. The hard mask layer and the second dielectric layer are etched through the first trench opening and the second trench opening, thereby forming a first dual damascene structure comprising a first trench and a first via, and a second trench in the second dielectric layer, respectively. A second photoresist pattern having a self-aligned via opening above the second trench is formed. The second dielectric layer is etched through the self-aligned via opening, thereby forming a second dual damascene structure comprising the second trench and a second via under the second trench.

A method of fabricating a semiconductor integrated circuit (IC) is disclosed. A dielectric layer is formed over a substrate. An interlayer is formed over the dielectric layer. A first photoresist layer with a first opening is formed over the interlayer and a second photoresist layer having a second opening is formed over the first photoresist layer. Spacers are formed along sidewalls of the first opening and the second opening. A first trench is formed in the interlayer by using the spacer along the first opening as an etch mask. A second trench is formed in the interlayer by using the spacer along the second opening as an etch mask. The first trench and the second trench are extended down into the dielectric layer as a lower portion and an upper portion, respectively, of a dielectric trench.

A method of forming a semiconductor device having a vertical metal line interconnect (via) fully aligned to a first direction of a first interconnect layer and a second direction of a second interconnect layer in a selective recess region by forming a plurality of metal lines in a first dielectric layer; and recessing in a recess region first portions of the plurality of metal lines such that top surfaces of the first portions of the plurality of metal lines are below a top surface of the first dielectric layer; wherein a non-recess region includes second portions of the plurality of metal lines that are outside the recess region.

A method of forming a semiconductor structure is disclosed. A multi-layer structure is formed over a substrate. A photoresist stack with a stepped sidewall is formed on the multi-layer structure. A pattern of the photoresist stack is transferred to the multi-layer structure.

A semiconductor structure includes a semiconductor device, a conductive line, a dielectric layer and a redistribution layer (RDL). The conductive line is present over the semiconductor device. The dielectric layer is present over the conductive line. The RDL includes a conductive structure over the dielectric layer and a conductive via extending downwards from the conductive structure and through the dielectric layer. The conductive via comprises a bottom portion, a top portion, and a tapered portion between the bottom and top portions, wherein the tapered portion has a width variation greater than that of the bottom and top portions.

A method of forming a semiconductor structure includes the following steps. A dielectric layer is formed over a conductive line. A photoresist layer is formed over the dielectric layer. The photoresist layer is patterned to form a mask feature and an opening is defined by the mask feature. The opening has a bottom portion and a top portion communicated to the bottom portion, and the top portion is wider than the bottom portion. The dielectric layer is etched to form a via hole in the dielectric layer using the mask feature as an etch mask, such that the via hole has a bottom portion and a tapered portion over the bottom portion. The conductive material is filled in the via hole to form a conductive via.

According to one embodiment, a template is provided with a transferring pattern on a first surface of a substrate. The transferring pattern includes a first projecting portion that projects from the first surface with a first height and extends in a first direction along the first surface, a second projecting portion that projects from the first surface with a second height higher than the first height and extends in a second direction along the first surface, a first columnar portion that is arranged at a position overlapping with the first projecting portion and has a top surface with a third height higher than the second height as a height from the first surface, and a second columnar portion that is arranged at a position overlapping with the second projecting portion and has a top surface with the third height as a height from the first surface.