Test System for Transmission Line Propagation Delay Measurement
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Solution Overview
Problem
As the number of semiconductor devices on a wafer increases, measuring the propagation delay time of transmission lines becomes more complex due to increased impedance mismatches and signal characteristics, leading to inaccuracies in propagation delay time measurement and subsequent signal compensation.
Innovation Solution
A test system that includes a signal generator, transmission/reception circuits, and a voltage generator to apply different reference voltages to transmission lines, allowing for the calculation of propagation delay times using various equations, thereby accounting for signal characteristics and impedance mismatches, and adjusting output clock signals accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of transmission lines is increased to accommodate more semiconductor devices on a wafer, then the productivity increases, but the measurement precision of propagation delay time deteriorates due to increased impedance mismatches and signal characteristics
Solution Approach 1:
The patent applies different reference voltages to different transmission lines based on their specific characteristics (number of branch lines). Transmission/reception circuits are configured with locally optimized reference voltages that match their respective transmission line environments, thereby maintaining measurement precision even as the total number of transmission lines increases
Solution Approach 2:
The patent changes the reference voltage parameter for each transmission line based on its characteristics. By adjusting the reference voltage level according to the number of branch lines, the system compensates for impedance mismatches and signal characteristic variations, maintaining accurate propagation delay time measurements across all transmission lines
2Measurement precision
If different reference voltages are applied to transmission/reception circuits to improve measurement accuracy, then the measurement precision improves, but the device complexity increases
Solution Approach 1:
The voltage generation system is segmented into multiple independent voltage generators, each associated with a specific transmission line. This segmentation allows each generator to be controlled independently based on its transmission line's characteristics, simplifying the overall control logic while achieving precise measurements
Solution Approach 2:
The patent uses a universal voltage generator design that can output multiple different reference voltages. This multi-functional voltage generator can serve multiple transmission lines with different characteristics, reducing the need for separate dedicated voltage sources for each line and thereby reducing overall system complexity
Data Source
AI summary
A test system includes a signal generator, a plurality of transmission/reception circuits and a voltage generator. The signal generator generates a test signal. The transmission/reception circuits are connected to a plurality of transmission lines. The transmission lines each include a main line and at least one branch line connected to the main line. The transmission/reception circuits provide the test signal to the transmission lines. The transmission/reception circuits detect a response signal corresponding to the test signal. The voltage generator supplies a first reference voltage and one of the second reference voltage greater than the first reference voltage and a third reference voltage between the first reference voltage and the second reference voltage to at least one of the transmission/reception circuits.