Merged Mandrel Patterns for Wide Power Rails
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Solution Overview
Problem
The existing self-aligned double patterning (SADP) scheme limits the width of metal lines due to regular photolithography processes, making it difficult to fabricate wide metal lines for high current capacity power rails, which increases manufacturing complexity and cost.
Innovation Solution
The method involves forming merged mandrel patterns with different dimensions using a block lithography process after conventional mandrel patterning, allowing for the creation of wide power rails with varied widths throughout the chip area, enabling the fabrication of wide metal lines for high electrical current applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional SADP photolithography processes are used to pattern metal lines, then manufacturing precision is maintained, but the metal line width is limited and cannot be widened for high current capacity applications
Solution Approach 1:
The patent divides the patterning process into multiple stages: first forming initial mandrels with conventional lithography, then forming spacers on mandrel sidewalls, removing mandrels, and repeating the process to create wider metal lines. This segmentation allows each stage to operate within its precision limits while achieving overall width expansion.
Solution Approach 2:
The patent transitions from two-dimensional planar patterning to three-dimensional spacer formation on mandrel sidewalls. By utilizing the vertical dimension and sidewall spacing, the effective horizontal width of metal lines can be doubled without requiring proportional increases in lithography resolution.
2Length of moving object
If additional masking and patterning steps are used to create wide metal lines, then metal line width can be increased, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
The patent merges the mandrel and spacer formation processes into a unified SADP sequence where spacers are self-aligned to mandrels. This merging eliminates the need for separate alignment steps and reduces the total number of lithography masks required, thereby simplifying the overall fabrication process while achieving wider metal lines.
Solution Approach 2:
The spacer formation process is self-aligned to the mandrel structure, automatically defining the position and width of subsequent metal lines without requiring additional alignment operations. This self-service mechanism reduces process complexity and improves manufacturing efficiency.
3Adaptability or versatility
If regular spacer patterns are used in SADP, then manufacturing precision is maintained, but adaptability to create varying metal line widths is lost
Solution Approach 1:
The patent applies different mandrel widths and spacer formation parameters at different locations on the wafer to create locally optimized metal line widths. Each region can be tailored to its specific current capacity requirements while maintaining precise patterning through the controlled SADP process.
Solution Approach 2:
The patent introduces dynamic control over mandrel dimensions and spacer deposition parameters, allowing the metal line width to be adjusted based on local design requirements. This dynamic approach enables versatile line width variation while preserving manufacturing precision through process control.
Data Source
AI summary
The present disclosure relates to semiconductor structures and, more particularly, to merged mandrel lines and methods of manufacture. The structure includes: at least one metal line having a first dimension in a self-aligned double patterning (SADP) line array; and at least one metal line having a second dimension inserted into the SADP line array, the second dimension being different than the first dimension.