Semiconductor Memory Internal Voltage Measurement via I/O Pad Sharing
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Solution Overview
Problem
In semiconductor memory devices, measuring internal voltages is challenging due to the complexity of internal circuits and the need for additional dummy pads, which are not usable for their original purpose and cannot be measured without special bonding during the packaging process.
Innovation Solution
An internal voltage measuring apparatus that utilizes a data output driver to output internal voltages through existing I/O pads, allowing for voltage measurement without requiring additional dummy pads by sharing I/O pads used for data input/output and activating a test signal to output internal voltages VCORE, VPP, VBB, and VBLP.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If special bonding is added to measure internal voltages, then internal voltage measurement capability is improved, but device complexity and manufacturing process complexity increase
Solution Approach 1:
The patent applies multi-functionality by enabling I/O pads to serve dual purposes: data input/output operations during normal operation and internal voltage measurement during test mode. The data output driver is configured to output internal voltages (Vcore, Vpp, Vbb, Vblr) through the same I/O pads used for data communication, eliminating the need for separate dummy pads or special bonding configurations.
2Measurement precision
If dummy pads are specially bonded to measure internal voltages, then internal voltage measurement is enabled, but the original purpose of address pins/balls is compromised
Solution Approach 1:
The patent implements dynamic functionality where the data output driver switches between two operational modes based on a test signal: normal data output mode during operation and internal voltage measurement mode during testing. This dynamic switching allows the same I/O pad to perform different functions at different times, maintaining full versatility without requiring permanent reconfiguration or special bonding.
3Measurement precision
If special bonding is performed during packaging manufacturing, then internal voltage measurement becomes possible, but manufacturing time and process complexity increase
Solution Approach 1:
The patent applies self-service by designing the data output driver to inherently possess the capability of outputting internal voltages through its existing circuit structure and I/O pads. No additional bonding operations, test structures, or special packaging modifications are required. The device uses its own resources (data output driver circuitry and I/O pads) to enable internal voltage measurement, eliminating the need for external assistance or complex packaging processes.
Data Source
AI summary
A semiconductor memory device includes a plurality of internal voltage measuring units, each for driving data input from a memory bank to output the data when a test signal is deactivated, and outputting a corresponding one of internal voltages used in the semiconductor memory device when the test signal is activated.