Semiconductor Integrated Circuit Well Proximity Effect Mitigation
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Solution Overview
Problem
The miniaturization of semiconductor integrated circuits leads to significant characteristic fluctuations in CMOS transistors due to the well proximity effect, making it difficult to achieve accurate and efficient circuit simulation, as the influence of this effect increases simulation and development time and costs.
Innovation Solution
The semiconductor integrated circuit design aligns the center locations of active regions with respect to the well boundary, equalizing the distances from the well boundary to the centers of active regions, thereby minimizing characteristic fluctuations caused by the well proximity effect, allowing for highly accurate circuit simulation without extensive modeling or evaluation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the well proximity effect is modeled and reflected to the circuit simulator, then simulation accuracy is improved, but simulation time and development time increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-aligning the center locations of active regions with respect to the well boundary during the layout design phase. This preliminary geometric arrangement equalizes the distances from the well boundary to the centers of active regions, thereby pre-compensating for the well proximity effect before simulation begins. As a result, the simulation can proceed without extensive well proximity effect modeling, reducing simulation time while maintaining accuracy.
2Measurement precision
If the well proximity effect is modeled and reflected to the circuit simulator, then simulation accuracy is improved, but development cost increases
Solution Approach 1:
The patent applies preliminary action by pre-aligning the center locations of active regions with respect to the well boundary during the layout design phase. This preliminary geometric arrangement equalizes the distances from the well boundary to the centers of active regions, thereby pre-compensating for the well proximity effect before simulation begins. As a result, the simulation can proceed without extensive well proximity effect modeling, reducing simulation time while maintaining accuracy.
3Productivity
If transistors are miniaturized to increase integration density, then productivity is improved, but characteristic fluctuation due to well proximity effect increases
Solution Approach 1:
The patent applies local quality by making the layout configuration specific to the local geometric relationship between active regions and well boundaries. By aligning the center locations of active regions with respect to the well boundary, the patent creates a localized geometric arrangement that equalizes the distances from the well boundary to the centers of active regions. This local geometric optimization compensates for the well proximity effect at the transistor level, maintaining characteristic stability even as transistors are miniaturized for higher integration density.
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 design approach reduces simulation errors and development costs by equalizing the influence of the well proximity effect across transistors, enabling faster and more accurate circuit simulation and design, while preventing increases in development period and cost.
Implementation Method 1
ions with high energies are implanted into the substrate
Implementation Method 2
some of impurity ions implanted at high energies scatter within the photoresist, and are emitted from the photoresist and then implanted into the well regions
Data Source
AI summary
An integrated circuit includes: a first well of a first conductivity type; a second well of a second conductivity type coming into contact with the first well at a well boundary extending in a gate length direction; a first transistor having a first active region of the second conductivity type provided in the first well; and a second transistor which has a second active region of the second conductivity type provided in the first well and differing from the first active region in length in a gate width direction. The center location of the first active region in the gate width direction is aligned with the center location of the second active region in the gate width direction with reference to the well boundary.