Dynamic Memory Word Line Kick Voltages for Uniform Ramp Rates
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Solution Overview
Problem
Existing semiconductor memory devices face challenges in achieving consistent ramp rates for word line voltages during programming and sensing operations, leading to inefficiencies and potential unreliability.
Innovation Solution
The method involves dynamically assigning different kick voltages to word lines based on their resistance capacitance, with slower-ramping word lines receiving higher kick voltages and faster-ramping word lines receiving lower kick voltages to achieve uniform ramp rates across the memory block.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single target voltage is applied to all word lines, then the circuit operation is simplified, but the ramp rates become inconsistent across different word lines
Solution Approach 1:
The patent applies different kick voltages to different word lines based on their individual ramp characteristics. Word lines are divided into groups (first group, second group, third group) with different kick voltages assigned to each group, creating local variations in voltage application that compensate for differences in word line resistance and capacitance, thereby achieving consistent ramp rates across all word lines.
Solution Approach 2:
The patent dynamically adjusts the target voltage for each word line by adding a kick voltage component during the ramp-up phase. The target voltage is time-dependent: it starts at a higher level (intended voltage + kick voltage) and then transitions to the intended voltage after a kick duration. This dynamic adjustment allows each word line to reach its target voltage at the same rate despite having different electrical characteristics.
2Manufacturing precision
If higher kick voltages are applied to slow-ramping word lines, then the ramp rate consistency is improved, but the voltage control complexity increases
Solution Approach 1:
The patent segments the word lines into multiple groups based on their ramp characteristics. At least three groups are defined: a first group with a first kick voltage, a second group with a second kick voltage, and a third group with a third kick voltage. This segmentation allows the complex problem of varying ramp rates to be divided into manageable groups, each requiring a specific kick voltage level, thereby simplifying the control mechanism while achieving uniform ramp rates.
Solution Approach 2:
The patent changes the voltage parameter (kick voltage) based on the specific characteristics of each word line group. By measuring or determining the word line resistance capacitance and assigning different kick voltages accordingly, the system adapts the voltage parameter to match the electrical characteristics of each group, achieving consistent ramp rates without requiring complex real-time control for each individual word line.
3Productivity
If kick voltages are dynamically adjusted for each word line, then the programming and sensing performance is improved, but the measurement and control difficulty increases
Solution Approach 1:
The patent performs preliminary measurement or determination of word line resistance capacitance before the actual programming or sensing operations. Based on these preliminary measurements, kick voltages are assigned to different word line groups in advance. This preliminary action allows the system to prepare the appropriate voltage compensation strategy before needing to perform the actual memory operations, thereby improving performance without requiring complex real-time measurements during critical operations.
Data Source
AI summary
The memory device includes an array of memory cells that are arranged in a plurality of word lines. The word lines of the memory block are associated with respective kick voltages. The kick voltages associated with at least some of the word lines are different than the kick voltages associated with at least some other of the word lines. In operation, circuitry sets a target voltage for at least one word line of the plurality of word lines at a magnitude that is equal to an intended voltage for the at least one word line plus the respective kick voltage that is associated with the at least one word line. After a kick duration, the circuitry proceeds reduces the target voltage for the at least one word line to the intended voltage.