Semiconductor Memory Column Repair Modes
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Solution Overview
Problem
The existing memory devices face challenges in increasing yield due to defects in memory cells, as they often require discarding entire devices when only a few cells are defective, leading to reduced product yield and flexibility in column repair operations.
Innovation Solution
The memory device is designed to support multiple column repair modes, allowing for flexible repair operations by using redundancy columns across different cell blocks based on stored repair information, enabling efficient replacement of defective columns in various configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If memory devices are discarded due to defective memory cells, then product quality is maintained, but product yield is negatively impacted
Solution Approach 1:
The patent applies preliminary action by pre-configuring redundancy memory cells and establishing repair operations before the memory device is put into service. When defects are detected during manufacturing testing, the repair operations are performed in advance to replace defective columns with redundancy columns, allowing the device to be salvaged rather than discarded. This proactive approach converts potentially defective devices into functional products, thereby improving yield while maintaining quality standards.
2Ease of repair
If column repair operations are performed using existing redundancy columns, then defective columns can be replaced, but the flexibility and efficiency of repair operations are limited
Solution Approach 1:
The patent implements dynamics by making the column repair operation adaptable and reconfigurable. The control logic can dynamically select different repair modes: using redundancy columns within the same cell block or borrowing redundancy columns from other cell blocks based on defect locations and availability. This dynamic flexibility allows the repair system to optimize its operation for different defect scenarios, improving both the ease of repair and the versatility of the repair operations.
Solution Approach 2:
The patent applies universality by designing redundancy columns that can serve multiple functions. The same redundancy column can be used to repair defective columns in different cell blocks depending on the configuration and defect pattern. The control unit can route repair operations to appropriate redundancy resources across the memory device, making the repair system universal rather than dedicated to specific cell blocks, thereby enhancing flexibility and efficiency.
Data Source
AI summary
A memory device including first to fourth cell blocks, each including a plurality of normal columns and one or more redundancy columns and a control unit suitable for repairing the normal columns using the redundancy columns in the first and the second cell blocks using first repair information and repairing the normal columns using the redundancy columns in the third and the fourth cell blocks using second repair information when the memory device is set as a first mode, and suitable for repairing the normal columns using the redundancy columns in the first and the third cell blocks using the first repair information and repairing the normal columns using the redundancy columns in the second and the fourth cell blocks using the second repair information when the memory device is set as a second mode.