Pitch-Aware Multi-Patterning Lithography Coloring
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Solution Overview
Problem
Current multi-patterning lithography technologies face challenges in ensuring the printability of integrated circuit designs, particularly due to shape-pairs at certain pitches exhibiting poor printability even when spacing is greater than the minimum spacing constraint, leading to issues with lithographic variation and electrical properties not meeting design specifications.
Innovation Solution
The method involves pitch-aware coloring for multi-patterning lithography, which considers not only the minimum spacing constraint but also individual values or ranges of preferred and forbidden pitches to create a coloring solution that increases occurrences of preferred-sized shapes and decreases forbidden-sized shapes, thereby improving printability by adjusting pitch values in the decomposed patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If shapes are decomposed into multiple masks for multi-patterning lithography, then the minimum spacing constraint is satisfied, but shapes at certain pitches still exhibit poor printability due to lithographic variation
Solution Approach 1:
The patent introduces pitch-aware coloring that goes beyond simple minimum spacing constraints by identifying and avoiding forbidden pitch ranges. The system calculates actual pitch values between shapes on the same mask and reassigns colors to shapes that fall within forbidden pitch ranges, thereby transforming the coloring parameters to eliminate printability issues while maintaining manufacturing feasibility.
2Device complexity
If traditional coloring methods are used that only consider minimum spacing, then the decomposition process is simple, but the printed shapes may have unacceptable lithographic variation
Solution Approach 1:
The patent implements a feedback mechanism where the system first performs initial coloring based on minimum spacing, then evaluates the actual pitch values of decomposed patterns. When forbidden pitches are detected, the system feeds this information back by reassigning colors to affected shapes, iteratively improving the printability until no forbidden pitches remain in the final mask decomposition.
3Manufacturing precision
If shapes are placed on different masks to satisfy minimum distance requirements, then spacing constraints are met, but pitch-aware printability is not optimized
Solution Approach 1:
The patent applies local quality by treating each shape-pair relationship individually based on its specific pitch value. Rather than applying a uniform coloring rule to all shapes, the system identifies shapes with forbidden pitch relationships and selectively reassigns their colors, thereby optimizing printability quality locally where needed while maintaining overall decomposition efficiency.
Data Source
AI summary
A method, system, and computer program product for improving printability of a design of an integrated circuit (IC) using pitch-aware coloring for multi-patterning lithography (MPL) are provided in the illustrative embodiments. A first shape is identified in a layout of the IC corresponding to the design as being apart by a first distance from a second shape. The first distance is a forbidden distance and at least equal to a minimum distance requirement of a lithography system. A determination is made that the first shape and the second shape are colored using a first color. The first shape is changed to a second color, such that even though the first distance is at least equal to the minimum distance requirement of the lithography system, the first and the second shapes are placed on different masks to print the design, thereby improving the printability of the design.