Semi-Damascene Metal Interconnect Layout for Higher Wiring Density
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Solution Overview
Problem
Traditional dual damascene line and via interconnect structure formation is insufficient to provide high metal wiring density as semiconductor devices scale down.
Innovation Solution
A device structure comprising integrated line-and-via structures with metallic barrier liners and main metal portions, and a method involving via and line cavity formation to create high-density metal interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If traditional dual damascene line and via interconnect structure formation is used, then manufacturing process is simpler, but metal wiring density is insufficient for scaled devices
Solution Approach 1:
The patent merges the via structure and line structure into a single integrated formation process. The via cavity and line cavity are formed simultaneously through a single etch process using the same mandrel, and the metal fill is deposited in one continuous operation. This integration of via and line formation increases metal wiring density while managing structural complexity through process consolidation rather than separate sequential steps.
2Area of moving object
If lateral dimensions of metal lines and vias are reduced to increase density, then metal wiring density improves, but traditional dual damascene formation becomes insufficient
Solution Approach 1:
The patent uses mandrels formed prior to the main etch process as preliminary structures that define both the via cavity and line cavity dimensions. These mandrels are formed with precise lateral dimensions through controlled deposition and patterning steps before the integrated etch process. This preliminary formation of dimensional references enables precise control of the final metal line and via dimensions at scaled sizes.
Solution Approach 2:
The mandrel structure serves as an intermediary element that transfers the pattern from the lithography step to the final metal interconnect structure. The mandrel acts as a temporary placeholder that defines the geometry of both vias and lines, enabling precise dimensional control during the integrated cavity formation process while being removed afterward.
3Productivity
If integrated line-and-via structures are formed, then metal wiring density increases, but manufacturing process complexity increases
Solution Approach 1:
The patent combines multiple formation steps into integrated processes: the via cavity and line cavity are etched simultaneously in one process, and the metal fill is deposited in one continuous operation filling both cavities. This merging of steps increases productivity by reducing the total number of process cycles, equipment transitions, and cycle times, while the process complexity is managed through careful sequencing and material selection.
Data Source
AI summary
A first integrated line-and-via structure includes a first via portion embedded within at least one via-level dielectric layer and a first line portion embedded within a lower portion of a dielectric matrix that contacts a top surface of the at least one via-level dielectric layer within a first horizontal plane. The first integrated line-and-via structure includes a first metallic barrier liner and a first main metal portion including a planar portion having sidewalls in direct contact with first surface segments of the dielectric matrix. A second integrated line-and-via structure includes a second via portion contacting the first line portion and further includes a second line portion adjoined to a top end of the second via portion.