OTP Memory Repair With Prevalidated Redundant Rows
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing memory devices with one-time programmable (OTP) cells face challenges in effectively repairing defective cells due to the inability to change the programmed state, leading to low yield rates and functional failures.
Innovation Solution
A method and device that includes a testing procedure to validate repair OTP cells before using them to replace invalid main OTP cells, ensuring only valid repair OTP cells are used for replacement, thereby improving yield rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant blocks of OTP cells are provided for replacement, then defective OTP cells can be repaired, but the repair effectiveness is limited because the OTP cells in redundant blocks may also be invalid
Solution Approach 1:
The patent applies preliminary action by performing a testing procedure on repair OTP cells before using them for repair. The controller tests each repair OTP cell to determine its validity status, and only valid repair cells are stored in the repair information. This preliminary validation ensures that when main OTP cells need repair, only guaranteed-valid repair cells are used, eliminating the risk of using invalid repair cells that would waste repair opportunities and reduce yield rate.
2Reliability
If OTP cells are programmed once, then data security is enhanced, but the ability to repair defective cells is compromised
Solution Approach 1:
The patent applies segmentation by dividing the OTP memory into distinct functional segments: main OTP cells for data storage and repair OTP cells for repair operations. Additionally, the repair OTP cells are segmented into valid and invalid categories through the testing procedure. This segmentation allows the system to maintain the one-time programmable security feature while creating a separate repair mechanism that can be independently validated and managed without compromising the security of the main data storage area.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a controller that mediates between the main OTP cells and repair OTP cells. The controller performs the testing procedure, determines validity, stores repair information, and executes the repair operation by programming the appropriate repair cell address into the main OTP cell. This intermediary layer enables the repair function while maintaining the one-time programmable nature of the original data storage cells, as the repair process is controlled and managed separately rather than directly modifying the secured data area.
3Device complexity
If repair procedures are performed without validating repair cells, then the process is simplified, but the yield rate decreases due to use of invalid repair cells
Solution Approach 1:
The patent applies self-service by enabling the memory device to automatically test and validate its own repair OTP cells during the manufacturing or initialization process. The controller performs the testing procedure internally, determines which repair cells are valid, and stores the repair information within the device itself. This self-validation mechanism eliminates the need for external manual testing and ensures that only proven-valid repair cells are available for use, thereby maintaining high yield rates without requiring complex external testing equipment or processes.
Data Source
AI summary
The present application discloses a method for operating a memory device. The memory device includes a plurality of rows of repair one-time programmable (OTP) cells and a plurality of rows of main OTP cells. The method includes performing a testing procedure to determine validities of the plurality of rows of repair OTP cells and store repair information to a first part of rows of repair OTP cells that are determined to be valid, and performing a repairing procedure to determine validities of the plurality of rows of repair OTP cells and repair at least one row of main OTP cells that is determined to be invalid in the plurality of rows of main OTP by using a second part of the rows of repair OTP cells that are determined to be valid.