Hexagonal Notch Mask Layout for Semiconductor Corner Rounding
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Solution Overview
Problem
In semiconductor manufacturing, the corner rounding phenomenon during the photolithography process leads to defects and reduced process margins due to the difficulty in forming precise patterns with rectangular notches in multi-height cells, often requiring multiple masks and increasing complexity and cost.
Innovation Solution
A method is introduced to generate a mask layout using a hexagonal notch design, where the edge of the hexagonal pattern is divided into fragments, and an optical proximity correction (OPC) model is used to estimate the target pattern's contour, calculate edge placement errors, and adjust fragment positions to minimize corner rounding without violating mask rule checks, allowing for the formation of multi-height cell structures with a single mask.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rectangular notch design is used in the mask layout, then the target pattern can be formed, but corner rounding phenomenon occurs during photolithography leading to defects and reduced process margins
Solution Approach 1:
The patent applies curvature by replacing the rectangular notch with a hexagonal notch design. The hexagonal shape with its angled sides and rounded corners naturally compensates for the corner rounding phenomenon that occurs during photolithography, ensuring that the final pattern matches the target geometry more accurately while maintaining adequate process margins.
Solution Approach 2:
The patent changes the geometric parameters of the notch from a rectangular shape to a hexagonal shape with specific side lengths and angles. This parameter transformation allows the mask pattern to pre-compensate for optical proximity effects, thereby controlling corner rounding and improving both manufacturing precision and process reliability simultaneously.
2Manufacturing precision
If multiple masks are used to form multi-height cell structures with rectangular notches, then pattern precision can be maintained, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the functionality of multiple masks into a single mask by implementing a hexagonal notch design that can form multi-height cell structures in one exposure step. This consolidation maintains pattern precision while reducing mask complexity and manufacturing overhead.
Solution Approach 2:
The hexagonal notch design serves multiple functions simultaneously: it controls corner rounding, enables multi-height cell formation, and maintains pattern precision. This universal design eliminates the need for separate masks for different pattern requirements, thereby reducing overall device complexity.
3Manufacturing precision
If a hexagonal mask pattern is placed on the preliminary rectangular mask pattern, then corner rounding is controlled, but the mask layout complexity increases
Solution Approach 1:
The patent segments the hexagonal mask pattern into discrete geometric elements that can be systematically applied to the rectangular notch. This segmentation allows for methodical implementation and verification, reducing the perceived complexity while maintaining the corner rounding control benefits.
Data Source
AI summary
A method of manufacturing a semiconductor device is provided as follows. A mask layout for forming a target pattern of a multi-height cell including a rectangular notch is generated. A preliminary rectangular mask pattern corresponding to the rectangular notch is detected from the mask layout. The multi-height cell is formed of standard cells arranged and connected to each other in a direction and the rectangular notch is disposed between two adjacent standard cells. A hexagonal mask pattern is, in response to the detecting of the preliminary rectangular mask pattern, placed on at least one short side of the preliminary rectangular mask pattern to generate a combined mask pattern. An outer boundary of the combined mask pattern remains in the mask layout and corresponds to the rectangular notch of the target pattern. A target mask and the semiconductor device are formed based on the combined mask pattern.