Narrow Line Formation via Spacer Transfer and Integrated Removal
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Solution Overview
Problem
Conventional photolithography processes are limited in forming separate narrow lines beyond lithographic resolution, requiring tedious two-lithographic processes like self-aligned double patterning (SADP) for high-density memory structures, which is inefficient.
Innovation Solution
A method that forms separate narrow lines by creating base patterns, spacers on the sidewalls, and transferring these patterns to the target layer, with integrated patterned removal treatment to disconnect connection segments, reducing the need for a specific lithographically defined mask layer and thus saving one lithography process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithography process is used, then manufacturing process is simple, but resolution is limited and cannot form separate narrow lines beyond lithographic resolution
Solution Approach 1:
The patent segments the pattern formation process into distinct stages: forming base patterns first, then forming spacers on their sidewalls. This segmentation allows the final narrow lines to be defined by the spacer width rather than direct lithography, enabling resolution beyond the lithographic limit while maintaining process manageability through staged fabrication.
Solution Approach 2:
The patent transitions from two-dimensional planar patterning to three-dimensional spacer formation on sidewalls. By utilizing the vertical dimension to create spacers that extend from the base patterns, the method achieves narrower effective line widths in the horizontal plane without requiring proportionally smaller lithographic features, thus overcoming resolution limits.
2Manufacturing precision
If self-aligned double patterning (SADP) technique is used to form separate narrow lines, then resolution beyond lithographic limit is achieved, but process becomes tedious requiring two lithographic processes
Solution Approach 1:
The patent merges the disconnecting of connection patterns with the removal of base patterns into a single integrated step. By designing the base patterns to include connection portions that are removed together with the base patterns themselves, the method eliminates the need for a separate lithographic step to disconnect connections, thereby reducing total process steps while maintaining the ability to form separate narrow lines.
Solution Approach 2:
The base patterns serve multiple functions: they define the positions of target lines, provide sidewalls for spacer formation, and include connection portions that define connection patterns. This multi-functionality reduces the need for separate dedicated structures and steps, streamlining the overall process while achieving the dual goals of high-resolution line formation and connection management.
3Adaptability or versatility
If base lateral patterns with greater width/pitch are used, then connection segments can be formed, but additional pattern complexity is introduced
Solution Approach 1:
The patent applies local quality by using base lateral patterns with greater width/pitch only in specific regions where connections are needed, while maintaining standard base line patterns elsewhere. This localized variation in pattern geometry provides the necessary connection capability in contact areas without increasing the complexity of the overall pattern set, as each pattern type remains relatively simple in its designated location.
Data Source
AI summary
A method for forming separate narrow lines is described. A target layer is formed over a substrate. Base patterns are formed over the target layer. Target line patterns and connection patterns between the ends of the target line patterns are formed as spacers on the sidewalls of the base patterns. The base patterns are removed. The target line patterns and the connection patterns are transferred to the target layer to form target lines and connection segments between the ends of the target lines. At least a portion of each connection segment is removed to disconnect the target lines while other area of the substrate is subjected to a patterned removal treatment.