Filler Cell Density Control for IC Layout Uniformity
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Solution Overview
Problem
As semiconductor manufacturing processes miniaturize, the complexity of integrated circuit designs increases, leading to non-uniform pattern densities which pose challenges in the fabrication process.
Innovation Solution
The use of standard cells with filler cells of varying densities, including back end of line (BEOL), middle of line (MOL), and front end of line (FEOL) patterns, allows for the adjustment and satisfaction of density rules in integrated circuit layouts through selective arrangement and placement of filler cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If standard cells are miniaturized to reduce size, then integration density improves, but pattern density uniformity deteriorates
Solution Approach 1:
The patent applies local quality by introducing filler cells with specifically designed pattern densities to correct density non-uniformities in local regions. Different filler cells (first type with higher density, second type with lower density) are selectively placed in different locations to achieve local density adjustment, thereby resolving the contradiction between miniaturization and density uniformity.
Solution Approach 2:
The patent changes the density parameter of patterns within filler cells to control overall pattern density distribution. By adjusting the density of patterns in filler cells (using different types with varying densities), the system can compensate for density variations caused by standard cell miniaturization while maintaining reduced cell sizes.
2Productivity
If circuit design complexity increases due to miniaturization, then integration capability improves, but pattern density control deteriorates
Solution Approach 1:
The patent uses local quality by implementing filler cells with different pattern densities at specific locations within the standard cell array. This allows localized control of pattern density to compensate for the loss of control caused by increased design complexity, enabling both high integration and good density control.
Solution Approach 2:
The patent changes pattern density parameters through selective placement of different filler cell types. This parameter adjustment mechanism provides a controlled way to manage pattern density distribution even as overall circuit design complexity increases, thereby maintaining manufacturing precision alongside integration capability.
3Manufacturing precision
If filler cells with different densities are used to adjust pattern density, then density rule satisfaction improves, but device complexity increases
Solution Approach 1:
The patent applies local quality by using different types of filler cells (with different pattern densities) only in specific locations where density adjustment is needed, rather than throughout the entire device. This localized approach improves density rule satisfaction while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent changes pattern density parameters by selectively introducing filler cells with different densities only where necessary to satisfy density rules. This targeted parameter adjustment achieves density control goals while avoiding unnecessary complexity from universal use of multiple filler cell types.
Data Source
AI summary
Provided is an integrated circuit including standard cells arranged over a plurality of rows. The standard cells may include: a plurality of functional cells each implemented as a logic circuit; and a plurality of filler cells including at least one first filler cell and at least one second filler cell that each include at least one pattern from among a back end of line (BEOL) pattern, a middle of line (MOL) pattern, and a front end of line (FEOL) pattern, and wherein the at least one first filler cell and the at least one second filler cell have a same size as each other, and a density of one of the at least one pattern of the at least one first filler cell is different from a density of one of the at least one pattern of the at least one second filler cell.