IC Dummy Feature Placement for CMP Uniformity
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Solution Overview
Problem
As semiconductor technologies advance to smaller feature sizes, existing methods for adding dummy features in integrated circuit (IC) design face limitations in tuning pattern density uniformity and effectiveness, particularly during chemical mechanical polishing (CMP) and electron-beam lithography, leading to issues like spatial charging and micro-loading effects, and increased simulation and calculation times.
Innovation Solution
A method for IC design and mask making that involves generating space blocks with optimized isolation distances and block dummy density ratios to efficiently insert dummy features, enhancing CMP and thermal annealing processes, correcting optical proximity effects, and improving imaging resolution through sub-resolution features and pattern density weighting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dummy features are inserted into the IC pattern to enhance CMP performance, then CMP uniformity is improved, but processing time and simulation complexity increase
Solution Approach 1:
The patent segments the dummy feature insertion process into distinct stages: identifying regions requiring dummy features, calculating optimal dummy feature parameters, and selectively inserting dummy features only in necessary areas. This segmentation reduces overall processing time while maintaining CMP uniformity improvements.
Solution Approach 2:
The patent performs preliminary analysis to identify regions that require dummy features before the actual insertion process. By pre-calculating which areas need enhancement and determining optimal dummy feature parameters in advance, the method avoids unnecessary processing and reduces simulation complexity.
2Manufacturing precision
If dummy features are inserted to improve pattern density, then CMP performance is enhanced, but spatial charging effect and micro-loading effect worsen
Solution Approach 1:
The patent applies local quality by inserting dummy features with specific properties only in regions where they are most needed. The method calculates optimal dummy feature density and distribution locally based on the specific characteristics of each region, rather than uniformly across the entire IC pattern. This localized approach improves pattern density uniformity while minimizing spatial charging effects in areas where dummy features are present.
3Manufacturing precision
If existing dummy feature methods are used, then CMP performance is improved, but degree of freedom and effectiveness to tune pattern density are limited
Solution Approach 1:
The patent implements dynamic dummy feature insertion by allowing the density, size, and distribution of dummy features to be adjusted based on local pattern requirements. The method calculates optimal dummy feature parameters dynamically for different regions of the IC pattern, providing flexibility in tuning pattern density while maintaining improved CMP performance.
Solution Approach 2:
The patent changes multiple parameters of dummy features including density, size, shape, and distribution to optimize both CMP performance and pattern density uniformity. By varying these parameters based on local requirements, the method achieves adaptability in tuning pattern density while maintaining the beneficial effects on CMP performance.
4Manufacturing precision
If various simulations and calculations are performed for dummy features, then pattern density uniformity is improved, but cost and processing time increase
Solution Approach 1:
The patent performs preliminary calculations to determine optimal dummy feature parameters before detailed simulations. By pre-establishing guidelines for dummy feature insertion based on simplified models, the method reduces the complexity and computational requirements of subsequent detailed simulations while maintaining pattern density uniformity improvements.
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 reduces processing time, improves pattern density uniformity, and enhances the effectiveness of fabrication processes by optimizing dummy feature placement, thereby addressing the challenges of smaller feature sizes and increasing the efficiency of lithography and CMP operations.
Implementation Method 1
CMP involves both mechanical grinding and chemical etching in the material removal process
Implementation Method 2
CMP involves both mechanical grinding and chemical etching in the material removal process
Implementation Method 3
when an electron-beam lithography technology is used to form the IC pattern
Data Source
AI summary
The present disclosure provides one embodiment of an IC method that includes receiving an IC design layout including a plurality of main features; choosing isolation distances to the IC design layout; oversizing the main features according to each of the isolation distances; generating a space block layer for the each of the isolation distances by a Boolean operation according to oversized main features; choosing an optimized space block layer and an optimized block dummy density ratio of the IC design layout according to pattern density variation; generating dummy features in the optimized space block layer according to the optimized block dummy density ratio; and forming a tape-out data of the IC design layout including the main features and the dummy features, for IC fabrication.