Flash Memory Self-Testing Using Known Good Die
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Solution Overview
Problem
The high cost of testing removable flash memory devices is a significant component of their overall cost, as conventional testers are expensive and elaborate, making it inefficient to test multiple flash memory dice effectively.
Innovation Solution
A low-cost test device coupled with a microcontroller on the removable memory device uses a known good flash memory die to electrically test candidate dice, minimizing the need for expensive testers and allowing for cost-effective production even if some dice are non-functional.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional testers are used to test removable flash memory devices, then testing accuracy and reliability are ensured, but testing cost and device complexity increase significantly
Solution Approach 1:
The removable flash memory device tests itself using its own onboard microcontroller and known good flash memory die, eliminating the need for external conventional testers. The device's microcontroller executes test sequences and evaluates candidate dice using the known good die as a reference, achieving self-diagnosis and self-testing functionality.
Solution Approach 2:
A known good flash memory die serves as an intermediary reference standard within the device. This reference die is used by the microcontroller to compare and evaluate the electrical characteristics of candidate flash memory dice, providing a reliable basis for testing without requiring complex external testing equipment.
2Measurement precision
If conventional testers are used to test multiple flash memory dice, then testing accuracy is maintained, but production efficiency and cost-effectiveness decrease
Solution Approach 1:
The device performs automated self-testing of multiple candidate flash memory dice using its onboard microcontroller, which executes test sequences and evaluates each die's electrical characteristics. This integrated approach enables efficient batch testing without requiring multiple expensive external testers, thereby improving production efficiency while maintaining accuracy.
Solution Approach 2:
A known good flash memory die is pre-installed on the removable memory device before production. This reference die is prepared in advance and used by the microcontroller to establish baseline electrical characteristics, enabling accurate comparison and evaluation of candidate dice during production without requiring complex pre-testing procedures.
3Reliability
If expensive conventional testers are used, then testing reliability is ensured, but overall device cost increases significantly
Solution Approach 1:
The removable flash memory device incorporates its own testing capability using an onboard microcontroller and known good flash memory die, eliminating the need for expensive external conventional testers. The microcontroller manages test sequences, controls electrical measurements, and evaluates candidate dice against the reference die, achieving reliable testing at minimal cost.
Solution Approach 2:
The known good flash memory die acts as an intermediary reference that enables reliable testing without requiring expensive external equipment. This reference die provides stable electrical characteristics that the microcontroller uses to compare and evaluate candidate dice, ensuring testing reliability while significantly reducing manufacturing costs by eliminating the need for expensive conventional testers.
Data Source
AI summary
A memory device may include a controller and a plurality of flash memory dice. The controller is provided for read and write access and communications with a host. However, the controller may also be utilized to test one or more of the flash memory dice mounted on the device. In this way, testing may be achieved with a relatively modestly priced tester by making use of the capabilities of the onboard controller. As a result, the cost of a memory device may be reduced in some cases.