Grid Clock Driver Layout for Reduced Chip Clock Skew
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Solution Overview
Problem
Conventional grid clock distribution networks face challenges in maintaining simultaneous clock signal delivery across a semiconductor chip, leading to phase offset or clock skew, which can limit operating speed and performance, especially between the outer boundary and the center of the chip.
Innovation Solution
The network includes clock drivers with varying driving capacities, arranged in a grid pattern with increased capacity towards the center of the chip, ensuring clock signals reach all areas simultaneously by adjusting the size or number of drivers and fine-tuning wiring density, thereby reducing clock skew.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If clock drivers with substantially the same driving capacity are arranged in a grid pattern, then the network structure is simple and easy to manufacture, but clock skew occurs between different areas of the chip
Solution Approach 1:
The patent applies local quality by varying the driving capacity of clock drivers based on their location within the chip. Clock drivers are configured with different driving capacities corresponding to their positions, with drivers farther from the chip center having greater driving capacity. This localized differentiation compensates for distance variations and reduces clock skew across different chip areas while maintaining overall network simplicity.
2Manufacturing precision
If clock drivers with varying driving capacities are used to reduce clock skew, then clock signal delivery precision is improved, but device complexity increases
Solution Approach 1:
The patent implements parameter changes by adjusting the driving capacity parameter of clock drivers based on their spatial location. Instead of using uniform drivers, the system varies the driving capacity parameter to compensate for distance differences from the chip center. This parameter adjustment reduces clock skew while avoiding the need for completely different driver architectures, thus limiting the increase in device complexity.
3Device complexity
If uniform clock drivers are arranged at regular intervals, then the distribution network structure is simple, but clock signals reach different areas at different times
Solution Approach 1:
The patent applies local quality by configuring clock drivers with location-specific driving capacities. Drivers positioned farther from the chip center are given higher driving capacity to compensate for the longer signal transmission distance. This localized adaptation ensures that clock signals reach all areas of the chip simultaneously, reducing time delay without requiring complex repositioning or additional buffering mechanisms.
Data Source
AI summary
A clock distribution network includes a plurality of clock drivers for outputting clock signals. At least one of the plurality of clock drivers has a driving capacity that is not equal to a driving capacity of at least another one of the plurality of clock drivers. The distribution network also includes a grid distribution network for distributing the clock signals output from the plurality of clock drivers.