Memory Bitline Shielding with Dynamic Shield Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As semiconductor memory devices, particularly DRAMs, increase in capacity by reducing the size of memory cells, the spacing between bitlines decreases, leading to coupling issues that cause errors during read operations and significant current leakage due to electrical bridges between bitlines and shield lines.
Innovation Solution
Incorporating shield lines between bitlines and using a shield line control circuit to manage the timing of shield voltage application based on operation modes and the presence of electrical bridges, preventing coupling and minimizing current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If more memory cells are included in a limited space by reducing cell size, then memory capacity is improved, but spacing between bitlines decreases leading to coupling issues and read errors
Solution Approach 1:
A shield line is introduced as an intermediary element positioned between adjacent bitlines. This shield line acts as a mediator that blocks the capacitive coupling between bitlines, preventing read errors while allowing the bitline spacing to be reduced for higher density. The shield line is controlled by a control circuit that activates it during read operations to maintain signal integrity.
2Reliability
If shield lines are continuously supplied with shield voltage, then coupling between bitlines is prevented, but current leakage through electrical bridges increases power consumption
Solution Approach 1:
Instead of continuously supplying shield voltage to the shield lines, the system uses periodic action by controlling the shield voltage based on operation modes. The shield line control circuit activates the shield voltage only during specific periods when coupling prevention is needed (such as during read operations), and deactivates it during other periods. This reduces unnecessary current leakage and power consumption while maintaining reliability when required.
Solution Approach 2:
The shield voltage supply is made dynamic rather than static. The shield line control circuit adjusts the shield voltage state based on detected operation modes, transitioning between active and inactive states as needed. This dynamic control allows the system to adapt to different operational requirements, activating shielding only when coupling is a risk and deactivating it to minimize power consumption during safe operational periods.
Data Source
AI summary
A memory device includes: a memory cell array including a plurality of memory cells; bitlines connected to the plurality of memory cells; shield lines, each being arranged between the bitlines; and a shield line control circuit configured to control a timing of supplying a shield voltage to the shield lines based on a command received from an outside of the memory device.