Well Tap Cell Decap Integration for Supply Noise Reduction
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Solution Overview
Problem
Integrated circuit designs face challenges in balancing the mechanical stress impacts on device performance due to shallow trench isolation regions, leading to increased well tap cell size and design complexity, particularly in sub-nanometer technology nodes.
Innovation Solution
Implementing decoupling capacitor structures within well tap cells using dummy transistors to mitigate supply noise and voltage drop issues without increasing chip area, by converting dummy transistors into decap structures that act as local current sources between supply and ground voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy transistors are included in well tap cells to meet LOD rules and prevent mechanical stress impacts, then device performance is improved, but well tap cell size increases significantly
Solution Approach 1:
The patent merges the LOD protection function with the decoupling capacitor function into a single integrated structure. The dummy transistors are configured to serve dual purposes: protecting against mechanical stress from STI regions and providing decoupling capacitance for supply noise reduction, thereby eliminating the need for separate structures and reducing overall cell area.
Solution Approach 2:
The dummy transistors are designed to perform multiple functions simultaneously: they act as LOD protection elements to prevent mechanical stress impacts, serve as decoupling capacitors for supply noise mitigation, and maintain uniform transistor performance. This multi-functionality reduces the number of separate components needed and minimizes cell area.
2Reliability
If dummy transistors are added to well tap cells to ensure uniform transistor performance, then device functioning is improved, but design complexity increases
Solution Approach 1:
The patent combines multiple design requirements into a single unified structure where dummy transistors simultaneously provide LOD protection, performance uniformity, and decoupling functionality. This integration simplifies the overall design process by reducing the number of separate components and their interconnections that would otherwise need to be designed and laid out.
3Object-affected harmful factors
If well tap cell size is increased to include dummy transistors for LOD compliance, then mechanical stress protection is improved, but chip area consumption increases
Solution Approach 1:
The patent integrates LOD protection transistors with decoupling capacitor structures, allowing the same physical components to serve both mechanical stress protection and electrical decoupling functions. This merging eliminates the need for additional separate structures that would otherwise increase chip area.
Solution Approach 2:
The dummy transistors are designed as universal elements that simultaneously provide mechanical stress protection through LOD compliance and electrical noise filtering through decoupling capacitance. This multi-functionality ensures that no additional area is required beyond what is already allocated for the dummy transistors themselves.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Improves power grid performance and reduces IR drop without requiring additional routing resources or silicon area, while maintaining footprint compatibility with existing well tap cells.
Implementation Method 1
converting dummy transistors into decap structures that act as local current sources between supply and ground voltages
Data Source
AI summary
An integrated circuit device and associated methods of fabrication and operation are provided with a standard well tap cell disposed over a semiconductor substrate having first and second regions, where the standard well tap cell includes a first tie transistor disposed between a first plurality of LOD protection transistors in the first region, and a second tie transistor disposed between a second plurality of LOD protection transistors in the second region, where the first plurality of LOD protection transistors and the second plurality of LOD protection transistors include a first transistor connected as a first decoupling capacitor between a first voltage supply and a second voltage supply, a second transistor connected as a second decoupling capacitor between the first voltage supply and the second voltage supply, and a plurality of additional dummy transistors, each having a gate, source, and drain terminal connected in common to a supply voltage.