Smart Refresh Device Row Hammer Mitigation
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Solution Overview
Problem
As semiconductor memory devices become more integrated, word line disturbances lead to data degradation due to increased coupling effects between adjacent word lines, resulting in data loss before memory cells are refreshed, necessitating a method to detect and mitigate word line activation imbalances.
Innovation Solution
A smart refresh device that includes an address control block to determine and store row hammer addresses, a repair control block to manage repair addresses, and a fuse block to output repair signals, enabling smart refresh operations by adding or subtracting decoding signals to adjacent word lines to prevent data degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the degree of integration of memory is increased, then the number of memory cells increases, but the coupling effect between adjacent word lines increases causing data degradation
Solution Approach 1:
The patent performs preliminary detection of row hammer addresses and pre-calculates repair addresses before data degradation occurs. The address control block identifies frequently activated word lines and proactively determines adjacent word lines that need refreshing, preventing data loss before it happens.
Solution Approach 2:
The patent implements a cushioning mechanism by storing repair addresses in advance and preparing repair control signals. When word line disturbance is detected, the pre-prepared repair information is immediately activated to protect against data degradation, acting as a buffer against the coupling effect.
2Length of stationary object
If the interval between word lines is reduced, then the degree of integration increases, but word line disturbance occurs causing data loss
Solution Approach 1:
The patent implements a feedback mechanism where the address control block continuously monitors word line activation patterns, detects row hammer addresses, and adjusts refresh operations accordingly. The system uses feedback from activation frequency to dynamically determine which adjacent word lines need repair, ensuring data integrity despite reduced spacing.
Solution Approach 2:
The patent changes operational parameters by dynamically adjusting refresh timing and target word lines based on detected activation patterns. Instead of uniform refreshing, the system modifies refresh parameters to target specifically affected word lines, maintaining reliability with reduced intervals.
3Speed
If frequent activation of a word line occurs, then data access speed improves, but adjacent memory cells suffer data degradation due to coupling
Solution Approach 1:
The patent applies local quality by treating different word lines differently based on their activation frequency. Instead of uniform treatment, the address control block identifies specific row hammer addresses and applies targeted refresh operations only to affected adjacent word lines, preserving data integrity where needed while maintaining high-speed access elsewhere.
Data Source
AI summary
A smart refresh device includes an address control block configured to determine whether a specific row address is a row hammer address, and invert a first row hammer address and perform an addition/subtraction of an address; a repair control block configured to determine whether the row hammer address is a repaired address and output a stored repair address as a second repair control signal; a repair address storage block configured to store an output address of the address control block and output a stored address as a latch address; a fuse block configured to output a repair signal representing information on a repair address to the repair control block, and output a decoding signal according to the latch address; and an operator configured to add and subtract the decoding signal according to an addition signal and a subtraction signal.