Integrated Circuit Layout Density Preservation
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Solution Overview
Problem
Integrated circuit design faces challenges in adjusting layout designs to conform to lithographic process limitations while preserving local density, as existing methods often result in shape violations and non-compliance with mask rule constraints during the conversion of secondary geometric elements into regular shapes.
Innovation Solution
The solution involves modifying geometric elements in integrated circuit layouts to maintain local density by adjusting their positioning and boundaries, ensuring compliance with mask rule constraints through techniques like Manhattanization and fine-tuning, while using methods to derive and preserve local density values within a threshold, ensuring the adjusted designs can be written to masks effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If geometric shapes are adjusted to conform to lithographic process limitations, then manufacturability is improved, but local density changes causing shape violations and non-compliance with mask rule constraints
Solution Approach 1:
The patent applies local quality by preserving the local density of geometric shapes during adjustment. Instead of uniformly modifying all shapes, the system calculates and maintains the density characteristics of each local region, allowing differential treatment of different areas based on their specific density requirements while ensuring mask rule compliance in each locale
Solution Approach 2:
The patent employs parameter changes by adjusting geometric parameters (such as shape boundaries and positions) while constraining the density parameter to remain within acceptable ranges. The system modifies shape parameters to achieve manufacturability while using density preservation constraints to prevent mask rule violations
2Manufacturing precision
If geometric shapes are adjusted to conform to lithographic process limitations, then printability is improved, but shape violations occur due to density changes
Solution Approach 1:
The patent implements feedback by continuously monitoring local density values during the shape adjustment process. The system calculates density metrics, compares them against target ranges, and uses this feedback to iteratively adjust geometric parameters, ensuring that printability improvements do not lead to shape violations
Solution Approach 2:
The patent applies preliminary action by pre-calculating acceptable density ranges and constraints before performing shape adjustments. The system establishes density preservation criteria in advance, which guide the adjustment process to prevent shape violations before they occur
Data Source
AI summary
The disclosed technology is related to adjusting an integrated circuit design while accounting for a local density of the design. In particular exemplary embodiments, a local density value for a layout design that defines a plurality of geometric shapes is derived. Subsequently, one or more of the geometric shapes are adjusted such that the local density value is preserved. With some implementations, the local density value is preserved if the adjusted local density value is within a threshold amount of the derived local density value.