Semiconductor Power Rail Layering to Reduce IR Drop
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor device sizes decrease, the narrow line widths and pitches of power rails and route tracks lead to significant IR drops and performance degradation due to high resistance in standard cell structures.
Innovation Solution
The power rails and route tracks are arranged in different layers without increasing size, allowing for wider dimensions and reduced resistance by separating them from signal tracks, thereby minimizing IR drops and enhancing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If power rails and route tracks are arranged in the same layer to simplify structure, then device complexity is reduced, but resistance increases due to narrow line widths and pitches causing significant IR drop
Solution Approach 1:
The patent applies dimensionality change by transitioning from a two-dimensional planar arrangement to a three-dimensional stacked arrangement. Power rails are placed in a first metal layer while signal tracks are placed in a second metal layer above it, utilizing the vertical dimension (z-axis) to separate power and signal paths. This resolves the contradiction by maintaining structural organization while enabling wider line widths and pitches within each layer, thereby reducing resistance and IR drop without increasing overall device complexity.
2Area of moving object
If line width and pitch of power rails are reduced to decrease cell size, then device miniaturization is achieved, but resistance increases causing performance degradation
Solution Approach 1:
By moving power rails to a separate metal layer (first metal layer) below the signal tracks (second metal layer), the patent enables wider line widths and pitches for power rails without increasing cell footprint. The vertical separation allows independent optimization of power and signal dimensions, reducing resistance and IR drop while maintaining miniaturized cell size in the planar direction.
Solution Approach 2:
The patent segments the metal interconnect system into distinct layers: power rails in the first metal layer and signal tracks in the second metal layer. This segmentation allows each layer to be optimized independently for its specific function, with power rails having wider dimensions for low resistance and signal tracks optimized for routing density, thereby resolving the contradiction between miniaturization and performance.
3Ease of manufacture
If power rails and signal tracks share the same layer to reduce manufacturing steps, then manufacturing complexity is reduced, but manufacturing precision decreases due to alignment difficulties
Solution Approach 1:
The patent utilizes vertical layering to separate power rails (first metal layer) and signal tracks (second metal layer), which eliminates the need for precise lateral alignment between power and signal features. Each layer can be patterned and formed independently through separate manufacturing steps, reducing alignment complexity while improving manufacturing precision through independent process control.
Solution Approach 2:
By segmenting the interconnect formation into separate manufacturing steps for different metal layers, the patent allows independent optimization of each layer's fabrication process. This segmentation enables precise control over power rail and signal track formation separately, improving manufacturing precision while the standardized multi-layer approach keeps overall manufacturing complexity manageable.
Data Source
AI summary
A semiconductor device includes a base, source, drain and gate electrodes, signal tracks and a power mesh. The source, drain and gate electrodes are arranged on a surface of the base, wherein the gate electrodes are extended along a first direction. The signal tracks arranged above the first surface of the base and above the source and drain electrodes and the gate electrodes, wherein the signal tracks are extended along the first directions. A power mesh is arranged below the first surface of the base, the power mesh comprising first power rails extended in the second direction and second power rails extended in a first direction, wherein the second direction is substantially perpendicular to the first direction.