Mask Pattern Correction for Lithography Diffraction
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Solution Overview
Problem
In lithography, the reduction in line width and distance between semiconductor components leads to optical diffraction issues, causing distortion in patterns due to the proximity of light-transmitting areas, resulting in necking or breaking of post-transfer patterns.
Innovation Solution
The method involves dividing the mask pattern into first and second patterns, forming slots on the transition areas between isolated and dense pattern areas, and performing optical proximity correction to disperse light energy, preventing excessive concentration and distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the interval between light-transmitting areas is reduced to achieve smaller component size, then the resolution is improved, but optical diffraction occurs causing pattern distortion
Solution Approach 1:
The patent applies preliminary action by performing optical proximity correction on the mask pattern before the actual lithography exposure. This involves pre-calculating and adjusting the mask pattern to compensate for expected optical diffraction effects, thereby maintaining resolution while avoiding pattern distortion caused by diffraction when light-transmitting areas are closely spaced.
Solution Approach 2:
The patent applies parameter changes by modifying the mask pattern parameters (such as line width, spacing, and shape) based on the density of surrounding light-transmitting areas. The correction adjusts these parameters to account for optical proximity effects, ensuring accurate pattern transfer even when components are closely spaced and diffraction is significant.
2Quantity of substance
If light passes through dense light-transmissive areas, then the pattern density is improved, but interaction with isolated areas causes pattern distortion
Solution Approach 1:
The patent applies local quality by applying different correction strategies to different regions of the mask pattern based on their density characteristics. Dense regions receive different proximity correction than isolated regions, with the correction amount and type varying locally to match the specific optical interaction characteristics of each area, thereby preventing pattern distortion while maintaining overall pattern density.
3Manufacturing precision
If optical proximity correction is performed to prevent pattern distortion, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
The patent applies copying by using computational models to create a virtual representation of the mask pattern and its optical effects. The proximity correction algorithm works with a digital copy of the mask pattern, calculating corrections based on stored optical characteristics and interaction rules, thereby achieving high precision without requiring complex physical correction mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively prevents necking or breaking of post-transfer patterns by dispersing light energy during exposure and development, maintaining pattern integrity and resolution.
Implementation Method 1
the light passing through the mask will be diffracted, thereby affecting the resolution of the transferred pattern
Data Source
AI summary
A method for correcting a mask pattern includes: providing an original mask pattern including at least one dense pattern area and at least one isolated pattern area, and the original mask pattern being divided into a first pattern and a second pattern, wherein the first pattern is formed in the isolated pattern area and extends to the dense pattern area, and the second pattern is formed in the dense pattern area; forming at least one slot on at least one section of the first pattern, and the at least one section of the first pattern is located on at least one transition area between the at least one isolated pattern area and the at least one dense pattern area; and performing an optical proximity correction operation on the first pattern formed with at least one slot and the second pattern. Using the corrected mask pattern may avoid the occurrence of necking or breaking on portion of the post-transfer pattern.