Mixed-Height Standard Cell Layout With Aligned Well Boundaries

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Solution Overview

Problem

Conventional standard cell libraries with mixed cell heights face design flexibility and manufacturing efficiency issues due to pattern irregularity and increased power consumption from extended metal interconnections, limiting the integration of cells with different heights in a single routing block.

Innovation Solution

A method for forming an integrated circuit layout by aligning well boundaries of mixed-height standard cells and shifting voltage rails to connect cells with different heights, ensuring continuous power and ground rails, thereby improving design flexibility and synthesis efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If standard cells with different cell heights are placed in the same routing block, then area efficiency is improved, but synthesis efficiency deteriorates due to pattern irregularity

Engineering Contradiction:

Improvearea efficiencyVSAvoidsynthesis efficiency

Core Design Contradiction:

Area of stationary objectVSProductivity

Solution Approach 1:

The standard cells are segmented into different height categories (first height and second height), allowing them to be organized in an alternating pattern rather than requiring uniform heights. This segmentation enables mixed-height placement while maintaining synthesis efficiency by creating a regular alternating pattern instead of irregular configurations.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention introduces asymmetric cell height arrangements by alternating between first-height and second-height standard cells in adjacent columns. This controlled asymmetry allows different cell heights to coexist in the same routing block while maintaining overall pattern regularity, thus improving area efficiency without sacrificing synthesis efficiency.

Inventive Principle:

Principle #4Asymmetry

2Area of stationary object

If standard cells with different cell heights are placed in the same routing block, then area efficiency is improved, but manufacturing precision deteriorates due to pattern irregularity

Engineering Contradiction:

Improvearea efficiencyVSAvoidmanufacturing process window

Core Design Contradiction:

Area of stationary objectVSManufacturing precision

Solution Approach 1:

By segmenting cells into discrete height categories and arranging them in a systematic alternating pattern, the invention creates predictable manufacturing patterns. This segmentation allows manufacturers to anticipate and prepare for specific pattern variations, thereby maintaining manufacturing precision despite the presence of mixed cell heights.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the height parameter of standard cells in a controlled, alternating manner rather than using arbitrary variations. This systematic parameter change creates predictable patterns that can be accommodated within the manufacturing process window, maintaining manufacturing precision while achieving area efficiency.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If standard cells with different cell heights are connected by metal interconnections, then design flexibility is improved, but power consumption increases due to extended interconnection length

Engineering Contradiction:

Improvedesign flexibilityVSAvoidpower consumption

Core Design Contradiction:

Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The invention resolves the contradiction by transitioning from horizontal metal interconnections to vertical direct connections. By stacking first-height and second-height cells alternately in adjacent columns, cells of different heights can be directly connected vertically, eliminating the need for extended horizontal metal interconnections and thereby reducing power consumption while maintaining design flexibility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

4Productivity

If conventional standard cell libraries with uniform cell heights are used, then synthesis efficiency is maintained, but area efficiency deteriorates

Engineering Contradiction:

Improvesynthesis efficiencyVSAvoidarea efficiency

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The invention introduces controlled asymmetry by alternating between first-height and second-height standard cells in adjacent columns. This asymmetric arrangement allows the circuit to achieve better area efficiency by optimizing cell heights for specific functions while maintaining synthesis efficiency through the regular alternating pattern.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

By segmenting the standard cell library into cells of different heights and organizing them in an alternating columnar pattern, the invention enables area optimization for different circuit functions while maintaining overall pattern regularity that preserves synthesis efficiency.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS20250356105A1Integrated circuit layout including standard cells and method to form the same

Publication Date: 2025.11.20 UNITED MICROELECTRONICS CORP

AI summary

A method for forming an integrated circuit layout including at least two standard cells having different cell heights is disclosed. The standard cells respectively have a well boundary to divide a PMOS region and an NMOS region. The standard cells are abutted side by side along their side edges in a way that the well boundaries of the cells are aligned along the row direction. The power rail and the ground rail of one of the standard cells are shifted to align and connect to the power rail and the ground rail of the other one of the standard cells.