Self-Aligned Multi-Metal Interconnects for Tight Line Spacing
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Solution Overview
Problem
Modern integrated circuits face challenges with interconnect resistances and separation distances between conductive lines due to aggressive dimensional scaling, leading to inefficiencies in metallic materials used for contacts and defects in high resistivity liner/barrier films, which affect the performance and reliability of semiconductor devices.
Innovation Solution
The formation of self-aligned multi-metallic interconnects using different metallic materials, where the second conducting lines are aligned using self-alignment material caps, allowing for controlled separation distances and manipulated resistive and capacitive characteristics, eliminating overlay constraints and improving pitch patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If aggressive dimensional scaling is applied to reduce interconnect dimensions, then wiring flexibility and integration density are improved, but interconnect resistances increase and separation distances between conductive lines become uncontrolled
Solution Approach 1:
The self-alignment material caps enable the second conducting lines to self-align with the first conducting lines through the cap structures, automatically achieving precise separation distances without requiring external lithographic alignment processes. This self-service mechanism eliminates overlay constraints and ensures uniform separation distances of 15 nm or less.
Solution Approach 2:
The self-alignment material caps act as intermediary structures between the first and second conducting lines. These caps provide a physical reference that mediates the positioning of the second conducting lines, ensuring precise alignment and controlled separation distances independent of lithographic alignment processes.
2Ease of manufacture
If conventional lithographic alignment is used to position second conducting lines, then manufacturing process simplicity is maintained, but overlay constraints and alignment defects occur
Solution Approach 1:
The self-alignment material caps enable the second conducting lines to self-align with the first conducting lines through the cap structures, automatically achieving precise separation distances without requiring external lithographic alignment processes. This self-service mechanism eliminates overlay constraints and ensures uniform separation distances of 15 nm or less.
3Reliability
If high resistivity liner/barrier films are used in interconnect structures, then electrical isolation is improved, but defects and manufacturing issues arise
Solution Approach 1:
The patent employs different metallic materials with optimized electrical and physical properties for first and second conducting lines. By changing the material parameters and selecting appropriate metals for each interconnect level, the patent achieves the required electrical isolation performance while avoiding the manufacturing defects associated with high resistivity liner/barrier films.
Data Source
AI summary
An interconnect structure is provided. The interconnect structure includes first conducting lines and second conducting lines. The first conducting lines are formed of a first metallic material and include at least one individual first conducting line in contact with a first corresponding substrate conducting line. The second conducting lines are formed of a second metallic material and include at least one individual second conducting line between neighboring first conducting lines and in contact with a second corresponding substrate conducting line. The at least one individual second conducting line is separated from each of the neighboring first conducting lines by controlled distances.