Flat Cell Placement on Non-Integer Multiple Height Rows

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Solution Overview

Problem

Current electronic circuit design tools are limited in optimizing the layout of digital integrated circuits with cells of different heights and widths, requiring separate sessions for placement and lacking the ability to handle Non-Integer Multiple Height (NIMH) rows, which restricts design optimization and integration of cells from different libraries.

Innovation Solution

A system and method for forming a global placement grid with local regions that support non-integer multiple height rows, allowing cells to be placed and associated within these regions during the same session, using a computer program product that includes modules for forming global and local placement grids and associating cells with local regions, enabling flat placement and legalization of cells across different heights and widths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate hierarchical placement sessions are used for different cell base heights, then placement operations can be performed on cells with different heights, but the operator cannot optimize design and layout across hierarchies and cannot perform dependent operations such as inserting clock trees and routing

Engineering Contradiction:

Improveability to handle cells of different heightsVSAvoiddesign optimization and integration efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The invention divides the placement grid into multiple hierarchical levels (first placement grid for first base height cells, second placement grid for second base height cells) while maintaining the ability to perform flat placement operations across all hierarchies in a single session, thus enabling both handling of different cell heights and design optimization

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The placement system is designed to handle multiple types of cells with different base heights using a unified flat placement approach, allowing the same placement session to optimize design and layout across all hierarchies and perform dependent operations like clock tree insertion and routing

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Ease of manufacture

If standard cell placement is based on a placement grid with row heights as exact-integer multiples of basic row, then placement can be performed on a standardized grid, but Non-Integer Multiple Height (NIMH) rows cannot be supported

Engineering Contradiction:

Improvestandardized placement processVSAvoidability to support NIMH rows

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The invention introduces local placement grids within the global placement grid that can have different row height characteristics, allowing specific regions to support NIMH rows while maintaining the standardized global grid structure for overall placement organization

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The system allows dynamic adjustment of placement grid parameters including row heights to accommodate both standard integer-multiple rows and non-integer multiple height rows, enabling flexibility in supporting different cell height requirements

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If cells from different libraries with different heights and widths are used, then design flexibility is improved, but separate hierarchical placement sessions are required which prevent optimization across hierarchies

Engineering Contradiction:

Improveuse of cells from different librariesVSAvoidplacement session management complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention merges the placement operations for cells from different libraries into a single flat placement session by coordinating multiple local placement grids within a unified global placement grid, eliminating the need for separate hierarchical sessions and enabling cross-hierarchy optimization

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS7802219B2Flat placement of cells on non-integer multiple height rows in a digital integrated circuit layout

Publication Date: 2010.09.21 CADENCE DESIGN SYST INC

AI summary

The various embodiments of the present invention generally relate to systems, methods, and computer program products for placement of at least one cell in a digital integrated circuit layout. A global placement grid of coordinates is formed, where the coordinates represent horizontal and vertical directions. A local placement grid of coordinates is also formed for at least one local region, where the local placement grid of coordinates represent horizontal and vertical directions, and where the at least one local region is adapted to support non-integer multiple height rows. At least one cell is associated with the at least one local region formed, and the cell can be placed in the local placement grid of the local region.