Trench Capacitor Tuning via Programmable Switches
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Solution Overview
Problem
Deep trench capacitors in semiconductor chips exhibit variations in capacitance due to process variations, affecting the performance of circuits requiring high precision capacitance, such as ring oscillators.
Innovation Solution
A capacitor structure with a parallel connection of trench capacitors, where first nodes are electrically tied and second nodes are connected through programmable electrical connections, including field effect transistors and electrically programmable fuses, allowing for tuning of total capacitance by temporarily or permanently disconnecting trench capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a parallel connection of multiple deep trench capacitors is used to increase total capacitance, then the capacitance value increases, but the capacitance variation increases due to process variations in individual capacitors
Solution Approach 1:
The patent applies dynamics by making the capacitor structure adjustable through programmable switching devices. The total capacitance can be dynamically tuned by selectively connecting or disconnecting individual trench capacitors using programmable electrical connections (fuses or transistors), allowing the system to adapt to achieve precise capacitance values despite manufacturing variations.
Solution Approach 2:
The patent changes the electrical connection parameters between capacitors by introducing programmable switching devices. By controlling the state (connected or disconnected) of each switching device, the effective capacitance of the parallel connection can be precisely adjusted to compensate for process variations and achieve high precision capacitance values.
2Ease of manufacture
If individual trench capacitor dimensions vary due to process variations, then manufacturing becomes easier, but the total capacitance precision deteriorates
Solution Approach 1:
The patent implements feedback by measuring the actual capacitance of the parallel connection and using programmable switching devices to adjust the total capacitance until it matches the target value. This closed-loop approach compensates for process variations in individual capacitor dimensions, allowing easy manufacturing while achieving high precision.
Solution Approach 2:
The programmable switching devices enable dynamic adjustment of the capacitor network configuration. By selectively enabling or disabling individual capacitors based on measured performance, the system can compensate for manufacturing variations while maintaining ease of fabrication.
3Manufacturing precision
If programmable electrical connections are added to enable capacitance tuning, then capacitance precision improves, but device complexity increases
Solution Approach 1:
The patent segments the capacitor structure into multiple independent trench capacitors, each with its own programmable switching device. This segmentation allows individual control of each capacitor unit, enabling precise tuning of the total capacitance while keeping each segment relatively simple in structure.
Solution Approach 2:
The programmable switching devices serve multiple functions: they act as connection switches, tuning elements, and compensation mechanisms simultaneously. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in overall device complexity while achieving high precision capacitance control.
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
This approach enables precise adjustment of capacitance, enhancing the performance of circuits by minimizing capacitance variations and achieving high precision capacitance values.
Implementation Method 1
Each programmable electrical connection can include at least one of a programmable electrical fuse and a field effect transistor, and can disconnect a corresponding trench capacitor temporarily or permanently.
Implementation Method 2
a programmable electrical fuse structure located on a semiconductor substrate
Data Source
AI summary
A capacitor structure can include a parallel connection of a plurality of trench capacitors. First nodes of the plurality of trench capacitors are electrically tied to provide a first node of the capacitor structure. Second nodes of the plurality of trench capacitors are electrically tied together through at least one programmable electrical connection at a second node of the capacitor structure. Each programmable electrical connection can include at least one of a programmable electrical fuse and a field effect transistor, and can disconnect a corresponding trench capacitor temporarily or permanently. The total capacitance of the capacitor structure can be tuned by programming, temporarily or permanently, the at least one programmable electrical connection.