Merged Dummy Poly Line for Mixed Poly Pitch Integration

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Solution Overview

Problem

The semiconductor industry faces challenges in controlling manufacturing variation, particularly in polysilicon critical dimension (CD) during integrated circuit processing, as existing design rules struggle to accommodate mixed poly pitches, leading to etch skew and device layout difficulties when incorporating non-default poly pitch cells into default cell devices.

Innovation Solution

An integrated circuit structure and system that intermixes default and non-default poly pitch cells by using merged dummy poly lines with portions complying with both pitches, ensuring predictability and reliability in device layouts by maintaining alignment and spacing between cells.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If dummy poly lines are inserted to control etch skew, then etch uniformity is improved, but layout complexity increases

Engineering Contradiction:

Improveetch uniformityVSAvoidlayout complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The merged dummy poly line serves multiple functions simultaneously: it acts as a dummy poly line for etch uniformity control in the first region, transitions to a functional poly line in the second region, and maintains proper spacing and alignment with adjacent cells. This multi-functionality eliminates the need for separate dummy poly lines and functional poly lines, reducing layout complexity while maintaining etch control.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the dummy poly line function with the functional poly line into a single merged structure. The merged dummy poly line continuously transitions from the first region through the boundary to the second region, integrating what would traditionally be separate elements into one unified structure that accomplishes both etch control and circuit functionality.

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If non-default poly pitch cells are used to meet specific circuit requirements, then circuit functionality is improved, but manufacturing precision deteriorates

Engineering Contradiction:

Improvecircuit functionalityVSAvoidpoly pitch control

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies different poly pitch characteristics to different regions: the first region uses default poly pitch for manufacturing precision and uniformity, while the second region uses non-default poly pitch for specific circuit functionality. The merged dummy poly line smoothly transitions between these regions, allowing each zone to have optimized properties for its specific purpose.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The merged dummy poly line acts as an intermediary structure that bridges the default poly pitch region and the non-default poly pitch region. It provides a continuous transition that maintains manufacturing control while enabling the non-default pitch cell to function properly, thus mediating between the conflicting requirements of uniformity and adaptability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If photolithography process is optimized for minimum pitch, then patterning precision is improved, but process window decreases for other pitches

Engineering Contradiction:

Improvepatterning precisionVSAvoidprocess window

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The merged dummy poly line is placed in advance at the boundary between default and non-default pitch regions to pre-establish proper spacing and alignment relationships. This preliminary structure ensures that the photolithography process can properly resolve both pitch types without requiring separate optimizations, as the transition region is pre-configured with appropriate dimensions and spacing.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7932566B2Structure and system of mixing poly pitch cell design under default poly pitch design rules

Publication Date: 2011.04.26 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

An integrated circuit including type-1 cells and a type-2 cell is presented. The type-1 cells have poly lines with a default poly pitch. The type-2 cell has poly lines with a non-default poly pitch. A first boundary region has at least one isolation area that lies between the type-1 cells and the type-2 cell in the X-direction. The first boundary region includes at least one merged dummy poly line, wherein the at least one merged dummy poly line has a first portion that complies with the default poly pitch of the type-1 cells and a second portion that complies with the non-default poly pitch of the type-2 cell.