Stack Memory Circuit Probe Pad Testing via Scanning
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Solution Overview
Problem
The existing stack-type memory systems face challenges in directly testing input/output-related components due to the small size of bump pads, making it difficult to perform external probing and testing.
Innovation Solution
The memory circuit and stack type memory system include exposed probe pads for external testing, along with a scanning circuit that generates sensing signals by sensing signals outputted through bump pads using reference voltage and test strobe signals, allowing for reliable input/output signal testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bump pads are used for input/output in stack-type memory systems, then signal transmission is enabled, but external probing and testing become difficult due to small pad size
Solution Approach 1:
The patent divides the testing function into two separate paths: a normal operation path using bump pads for signal transmission, and a testing path using probe pads for external probing. This segmentation allows each component to optimize for its specific function without compromising the other.
Solution Approach 2:
The scanning circuit acts as an intermediary that bridges the bump pad (internal) and probe pad (external). It senses signals from the bump pad and transfers them to the probe pad, enabling external testing of internal components without direct access to the bump pad.
2Difficulty of detecting and measuring
If probe pads are exposed for external testing, then testability is improved, but the physical structure becomes more complex
Solution Approach 1:
The probe pad serves multiple functions: it acts as both an output pad for normal operation and an exposed testing interface for external probing. The scanning circuit also serves dual purposes by enabling both internal signal transmission and external testing capabilities.
Solution Approach 2:
The patent adds a vertical dimension to the pad structure by exposing probe pads through the stack structure, creating an external access dimension while maintaining the internal bump pad connections. This allows testing access from the exterior without compromising internal signal paths.
3Difficulty of detecting and measuring
If scanning circuit is added to sense bump pad signals, then testing capability is enhanced, but device complexity increases
Solution Approach 1:
The scanning circuit is merged with the existing input/output path circuit, combining the signal transmission function and signal sensing function into a unified circuit structure. This integration minimizes additional complexity while achieving the testing capability.
Solution Approach 2:
The scanning circuit uses the existing bump pad signals to generate sensing signals for testing, allowing the circuit to test itself without requiring separate test signal generation infrastructure. The same signal path serves both operational and testing purposes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables reliable testing of input/output components by allowing direct external probing and monitoring of signal levels and timing parameters, enhancing test reliability and accuracy.
Implementation Method 1
a scanning circuit configured to generate a sensing signal by sensing a signal outputted through the bump pad while performing scanning of at least one of a reference voltage and a test strobe signal
Data Source
AI summary
A memory circuit may be provided. The memory circuit may include a memory array. The memory circuit may include an input and output path circuit coupled to a probe pad and a bump pad, and may be configured to input and output a signal between an exterior of the memory circuit and the memory array. The memory circuit may include a scanning circuit configured to generate a sensing signal by sensing a signal outputted through the bump pad while performing scanning of at least one of a reference voltage and a test strobe signal.