Semiconductor Test System Skew Correction via Calibration Board
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Solution Overview
Problem
Conventional test systems for semiconductor apparatuses are time-consuming and costly due to the use of probe needles and expensive robotic equipment for measuring and correcting signal timing skews in ASICs.
Innovation Solution
A test system comprising a calibration board with stored skew information and a main board capable of performing first and secondary skew corrections using test signals, where the calibration board stores skew data and the main board adjusts signal delays to synchronize I/O terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If probe needles and robotic equipment are used to measure and correct signal timing skews, then measurement precision is improved, but testing time increases and costs increase
Solution Approach 1:
The patent pre-calculates and stores skew correction values in a lookup table during the design phase. During actual testing, the system only needs to query the table using measured skew values as indices, rather than performing complex real-time calculations. This preliminary preparation dramatically reduces testing time while maintaining measurement precision.
Solution Approach 2:
The patent creates a simplified virtual model of the signal transmission paths and stores it in the lookup table. Instead of physically probing each signal path with expensive robotic equipment, the system uses the pre-stored virtual model to determine skew corrections. This copying approach eliminates the need for repeated physical measurements while preserving measurement accuracy.
2Measurement precision
If probe needles and robotic equipment are used to measure and correct signal timing skews, then measurement precision is improved, but testing costs increase
Solution Approach 1:
The patent replaces expensive, complex robotic probing systems with a simple, low-cost lookup table implementation. The lookup table can be implemented using basic memory components or even simple logic circuits, eliminating the need for costly robotic equipment while maintaining the ability to achieve precise skew measurements through pre-calculated correction values.
Solution Approach 2:
The patent extracts the complex real-time calculation functionality from the testing system and moves it to the design phase, where it can be performed once using software tools. The testing system itself only needs to perform simple table lookups, removing the need for expensive robotic equipment and complex real-time computation hardware.
3Measurement precision
If complex robotic probing systems are used for skew correction, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the mechanical robotic probing system with an electronic lookup table-based system. Instead of using physical robots to measure and adjust each signal path, the system uses pre-calculated correction values stored in memory, accessed through simple electronic indexing based on measured skew parameters. This substitution dramatically simplifies the device while maintaining measurement precision.
Solution Approach 2:
The patent changes the approach from continuous real-time adjustment by robotic systems to discrete parameter-based correction using pre-calculated values. The lookup table is indexed by measured skew parameters, and the corresponding pre-determined correction values are applied, transforming a complex continuous control problem into a simple parameter lookup and application process.
Data Source
AI summary
A test system for a semiconductor apparatus that includes a calibration board having first skew information therein and outputting a plurality of test signals, and a main board configured to perform first skew correction for correcting skews of the test signals based on the first skew information and perform secondary skew correction for correcting an I/O skew thereof using the plurality of test signals.