Flash Memory Word Line Charging via Dual-Voltage Switch
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Solution Overview
Problem
Conventional flash memory word lines have high resistance due to poly material, leading to slow charging times and reduced read/program operation speeds, especially as memory designs become thinner and smaller, making it difficult to accommodate metal straps for reducing resistance.
Innovation Solution
Incorporating a switch connected to a second operational voltage at the end terminal of the word line, which is turned on during charging to provide an additional charging path, reducing the overall resistance and speeding up the charging process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If metal straps are formed between start and end terminals of each word line to reduce resistance, then charging speed is improved, but device area increases and cannot be accommodated in thin and small memory designs
Solution Approach 1:
Multiple word lines share common metal straps instead of each word line having its own dedicated strap. The metal straps are merged into shared resources that serve multiple word lines simultaneously, reducing the total area occupied while maintaining the resistance reduction benefit for charging acceleration
Solution Approach 2:
The metal straps are designed to serve multiple functions: they act as charging paths for multiple different word lines during read/program operations, and can be controlled to provide charging current on demand. This multi-functionality allows the same physical structure to benefit multiple word lines without requiring separate straps for each
2Ease of manufacture
If poly material is used for word lines, then manufacturing is simplified, but resistance is high causing slow charging
Solution Approach 1:
The word line structure uses a composite configuration combining poly material (for the word line itself) with metal material (for the charging straps). The metal straps are connected to the poly word line terminals to provide low-resistance charging paths, while the poly material maintains ease of manufacture for the word line structure
Solution Approach 2:
The word line system is segmented into two functional parts: the poly word line structure (maintaining manufacturing simplicity) and the metal charging straps (providing low resistance). The segmentation allows each material to be optimized for its specific function while working together as a unified system
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 approach significantly reduces the resistance of the word line, thereby accelerating the read/program operations and addressing the space constraints in thinner memory designs by minimizing the number of connection lines required, which is less than half the number of metal straps needed in prior art.
Implementation Method 1
the first switch is simultaneously turned on to provide another charging path for the first word line
Data Source
AI summary
A memory and method for charging a word line thereof are disclosed. The memory includes a first word line driver, a first word line and a first switch. The first word line driver is connected to a first operational voltage for receiving a first control signal. The first word line comprises a start terminal connected to an output terminal of the first word line driver. The first switch is connected to a second operational voltage and an end terminal of the first word line. The second operational voltage is not smaller than the first operational voltage. When the first word line driver is controlled by the first control signal to start charging up the first word line, the first switch is simultaneously turned on to provide another charging path for the first word line until the first word line is charged to the first operational voltage.