Dummy Bit Line Potential Control for Leakage Reduction
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Solution Overview
Problem
In semiconductor devices with vertically structured transistors, dummy bit lines are not necessarily formed in a predetermined shape, leading to potential leakage currents due to non-uniform insulating films, which increases standby current and affects device reliability.
Innovation Solution
The semiconductor device incorporates a configuration with first and second dummy bit lines, where the first dummy bit line is insulated and supplied with a fixed potential, and the second dummy bit line is adjacent to the bit line, supplied with a voltage that matches the bit line's pre-charging potential, ensuring uniform electrical potential environments for bit lines and reducing leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If dummy bit lines are not formed in a predetermined shape to reduce device complexity, then device complexity is reduced, but leakage currents increase due to non-uniform insulating films
Solution Approach 1:
The patent applies equipotentiality by supplying a fixed potential to the first dummy bit line and substantially the same potential as the bit line pre-charging potential to the second dummy bit line. This creates uniform electrical potential environments that prevent potential differences across the insulating films, thereby eliminating leakage currents while maintaining a simplified dummy bit line configuration.
Solution Approach 2:
The patent changes the electrical potential parameter of the dummy bit lines to resolve the contradiction. By setting specific fixed potentials on the dummy bit lines rather than leaving them floating or uncontrolled, the insulating films maintain uniform electrical characteristics, preventing leakage without requiring complex geometric formations.
2Reliability
If dummy bit lines are formed with complex predetermined shapes to ensure uniform insulating films, then leakage currents are prevented, but device complexity increases
Solution Approach 1:
Instead of using complex geometries to ensure uniform insulating films, the patent uses equipotentiality by applying fixed potentials to the dummy bit lines. This electrical approach replaces the need for complex physical shapes, maintaining reliability while reducing structural complexity.
Solution Approach 2:
The patent changes from controlling the geometric parameters of dummy bit lines to controlling their electrical potential parameters. This parameter transformation allows leakage prevention through electrical means rather than complex structural design, resolving the contradiction between reliability and device complexity.
3Reliability
If multiple dummy bit lines with different potentials are used to control leakage currents, then leakage current is reduced, but device complexity increases
Solution Approach 1:
The patent segments the dummy bit line function into two distinct types: the first dummy bit line with fixed potential and the second dummy bit line with bit line pre-charging potential. This segmentation allows each dummy bit line to serve a specific leakage prevention purpose, achieving reliable standby current control while maintaining manageable device complexity through functional differentiation rather than complex unified control.
Data Source
AI summary
A semiconductor device includes a first signal wiring, a first dummy wiring, and a second dummy wiring. The first signal wiring is configured to be supplied with a first signal potential. The first dummy wiring is insulated from the first wiring. The first dummy wiring is configured to be supplied with a fixed potential. The second dummy wiring is disposed between the first signal wiring and the first dummy wiring. The second dummy wiring is insulated from the first dummy wiring. The second dummy wiring is configured to be supplied with substantially the same potential as the first signal potential.