PLD Output Feedback Paths for Complete Wafer-Level IOB Testing
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Solution Overview
Problem
Testing of programmable logic devices (PLDs) at the wafer level is challenging due to unbounded IOB pads, which prevents full evaluation of output signals since not all IOB pads are bonded to physical pins, hindering early defect detection and comprehensive testing.
Innovation Solution
Implementing feedback paths that allow output signals to be redirected back to the core module and rerouted to bonded IOB pads for measurement, enabling comprehensive testing even when some IOB pads are not yet bonded to physical pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If wafer level testing is performed on PLDs, then early defect detection is enabled, but testing cannot be completed for IOB pads not bonded to physical pins
Solution Approach 1:
The patent introduces feedback paths as intermediary signal routes that connect output logic modules back to input logic modules. These feedback paths serve as mediators that allow output signals from unbonded IOB pads to be redirected and measured through alternative bonded pads, enabling complete wafer-level testing without requiring all IOB pads to be physically bonded.
2Reliability
If all IOB pads are made accessible for testing, then comprehensive testing is achieved, but device complexity increases
Solution Approach 1:
The feedback paths are designed with multi-functionality, serving both as test signal routes and as functional signal paths for the normal operation of the PLD. This universal design allows the same structural elements to support both testing and operational functions, minimizing additional complexity while achieving comprehensive testing capability.
Data Source
AI summary
In one embodiment, an integrated device is disclosed. For example, in one embodiment of the present invention, a device comprises a core module for providing one or more output signals. The device comprises an output logic module for receiving the one or more output signals and an input logic module, wherein the one or more output signals are received by the input logic module via one or more feedback paths, where the one or more output signals are forwarded back to the core module.