Semiconductor Memory In-Operation Testing via Data Sampling
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Solution Overview
Problem
Existing semiconductor memory devices cannot be tested for errors while in operation due to the need for additional space to store test data and the requirement for BIST operations to be performed before installation, making it impossible to detect or handle errors during system use.
Innovation Solution
A semiconductor device and method that tests the memory device by sampling data written into it, storing a data sample, and comparing it with data read from the device, allowing for testing during an idle state without additional storage for test data, using a memory controller with a test controller that samples data, stores it, and compares it with data read from the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional BIST operations are used to test the semiconductor memory device, then testing capability is provided, but additional storage space is required and testing can only be performed before installation
Solution Approach 1:
The memory controller is designed to perform both normal memory control functions and self-test functions using the same data storage resources. The data storage unit serves dual purposes: storing normal operational data and storing test data for BIST operations, eliminating the need for separate dedicated test storage space.
Solution Approach 2:
The memory controller performs self-testing using its own operational data. By sampling data that is normally written to the memory device and comparing it with read data, the system uses its own operational resources for testing without requiring external test equipment or additional dedicated test structures.
2Reliability
If traditional BIST operations are used, then testing is performed, but testing can only be done before installation in the system
Solution Approach 1:
The testing capability is made dynamic by enabling tests to be performed at multiple stages: before installation and during operational use. The memory controller can initiate BIST operations at any time based on system conditions, allowing adaptive testing throughout the device lifecycle rather than being restricted to a single pre-installation timing.
Solution Approach 2:
The system maintains continuous monitoring capability by periodically performing BIST operations during normal operation. The memory controller continuously samples operational data and can initiate comparison tests without interrupting normal memory functions, ensuring ongoing error detection capability throughout the device's operational life.
3Reliability
If data sampling is performed during normal operation, then in-operation testing is enabled, but additional data storage is required
Solution Approach 1:
The data storage unit is designed to serve multiple functions simultaneously: storing normal operational data for memory operations and storing sampled test data for BIST operations. This multi-functional design eliminates the need for separate dedicated test data storage space while enabling continuous in-operation testing.
Solution Approach 2:
The patent merges the test data storage function with the normal operational data storage function into a single data storage unit. By combining these functions, the system achieves in-operation testing capability without increasing the total storage space requirement, as the same storage resources serve both operational and testing purposes.
Data Source
AI summary
A semiconductor device may test a semiconductor memory device by storing a data sample that is sampled from among data requested to be written into a semiconductor memory device and by comparing the data sample with data read from the semiconductor memory device which corresponds to the data sample.