Clock Buffer Placement in Semiconductor ICs
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Solution Overview
Problem
Conventional semiconductor integrated circuit devices face challenges in reducing clock skew, which affects performance, especially at higher frequencies, due to irregularities in clock signal delay, leading to increased wiring costs, power consumption, and reduced flexibility in circuit element arrangement.
Innovation Solution
A semiconductor integrated circuit device design that includes clock buffers at strategically determined intersecting points within a pseudo mesh covering the circuit elements, with main wirings transmitting clock signals to these buffers, optimizing buffer placement and size based on load and current driving capability to minimize skew and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If buffers are arranged at all intersecting points of a mesh covering the chip, then clock skew is reduced, but power consumption increases and circuit area increases
Solution Approach 1:
The patent applies local quality by selectively placing buffers only at intersecting points where circuit elements are actually located, rather than at all mesh intersecting points. This creates a non-uniform buffer distribution that matches the actual circuit element density, reducing unnecessary power consumption while maintaining clock skew control where needed.
Solution Approach 2:
The patent uses partial action by placing buffers at only some intersecting points (those coinciding with circuit elements) rather than all intersecting points of the mesh. This partial placement is sufficient to control clock skew for actual circuit elements while avoiding the excessive power consumption of placing buffers at every mesh intersection.
2Reliability
If buffers are arranged at all intersecting points of a mesh covering the chip, then clock skew is reduced, but circuit area increases
Solution Approach 1:
The patent applies local quality by concentrating buffers only where circuit elements are located, creating a targeted buffer placement strategy. This reduces the overall circuit area by eliminating buffers from regions where no circuit elements exist, while maintaining adequate clock distribution coverage.
Solution Approach 2:
The patent extracts unnecessary buffers from the clock distribution network by removing them from intersecting points where no circuit elements are present. This leaves only the essential buffers needed for actual clock loading, reducing circuit area while maintaining clock skew control.
3Reliability
If symmetric wiring arrangements are used, then clock skew is reduced, but wiring flexibility decreases and wiring cost increases
Solution Approach 1:
The patent embraces asymmetry by allowing irregular buffer placement at intersecting points that coincide with circuit elements, rather than enforcing symmetric mesh patterns. This asymmetric placement adapts to the actual circuit element distribution, maintaining clock skew control while improving wiring flexibility and reducing costs.
Solution Approach 2:
The patent introduces dynamics by making the buffer placement adaptable to the actual circuit element layout rather than following a fixed symmetric mesh pattern. This dynamic placement strategy allows the clock distribution network to adapt to varying circuit element positions, improving flexibility while controlling clock skew.
Data Source
AI summary
This invention concerns a semiconductor integrated circuit device comprising a plurality of circuit elements arranged in a chip and operating in response to a same clock signal; clock buffers arranged at intersecting points decided based on positions of the plurality of circuit elements, the intersecting points being included in intersecting points of a pseudo mesh virtually assumed to cover up a region in the chip including the plurality of circuit elements; and a main wiring transmitting the clock signal to the clock buffers.