Semiconductor Memory Self-Test via Internal Clock Multiplication
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Solution Overview
Problem
Conventional semiconductor memory test devices struggle to efficiently perform high-speed memory tests due to the mismatch in clock frequencies between external test devices and high-speed semiconductor memory devices, limiting the generation of various test data patterns and hindering the utilization of high-rate operating frequencies.
Innovation Solution
A test device integrated within the semiconductor memory device, comprising a clock frequency multiplier, data input and output buffers, and a test data generator, which multiplies the external clock signal to generate an internal high-frequency clock and synchronizes test data using control signals to produce diverse test patterns, enabling effective high-speed memory testing with low-speed external test devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the clock frequency of the external test device is increased to match high-speed semiconductor memory devices, then the test speed and efficiency are improved, but the manufacturing cost increases significantly
Solution Approach 1:
The semiconductor memory device performs self-testing by generating internal high-frequency clock signals and test data patterns independently, eliminating the need for expensive high-speed external test devices. The device uses its own high-speed internal clock to write and read test data, allowing it to self-diagnose defects without external assistance.
Solution Approach 2:
The external test device operates at a lower, standardized clock frequency but can test semiconductor memory devices operating at various high speeds through the self-testing mechanism. The universal low-speed external test device interface can accommodate high-speed memory devices by leveraging their internal high-frequency capabilities for self-testing.
2Productivity
If the clock frequency of the external test device is increased to match high-speed semiconductor memory devices, then the test coverage is improved, but the device complexity increases
Solution Approach 1:
The semiconductor memory device generates its own internal high-frequency clock signals and test data patterns, eliminating the need for complex high-speed external test equipment. The self-testing mechanism uses internal resources to perform comprehensive tests without requiring sophisticated external instrumentation.
Solution Approach 2:
The testing functionality is merged with the semiconductor memory device itself, combining the test data generator, clock frequency multiplier, and memory testing operations into a single integrated system. This eliminates the need for separate complex external test devices and reduces overall system complexity.
3Adaptability or versatility
If downward clock frequency adjustment is performed to match the external test device, then the compatibility is improved, but the test efficiency deteriorates
Solution Approach 1:
Instead of adjusting the external test device's clock frequency upward to match high-speed memory devices, the approach is inverted: the memory device performs self-testing using its own high-frequency internal clock. This reverses the traditional testing paradigm and maintains both compatibility and high test efficiency.
Solution Approach 2:
The semiconductor memory device independently generates internal high-frequency clock signals and test data patterns, allowing it to perform comprehensive testing at its native high speed without requiring external frequency adjustment. This self-service approach maintains both compatibility with standard test interfaces and high test efficiency.
Data Source
AI summary
A test device for a semiconductor memory device includes a clock frequency multiplier, a data input buffer, a test data generator and a data output buffer. The clock frequency multiplier multiplies an external clock signal having a relatively low frequency provided from an external test device to generate an internal clock signal having a relatively high frequency. The data input buffer buffers test pattern data provided in synchronization to the external clock signal to output the buffered test pattern data. The test data generator generates test data that is to be synchronized to the internal clock signal, using the outputted test pattern data based on a first or a second control signal. The data output buffer outputs the generated test data to a memory core of the semiconductor memory device. The test device generates various test data suitable for a memory test at a high operating speed.