Programmable Fuse Stitch Chain for Die-Level Interconnect Testing
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Solution Overview
Problem
Obtaining board level reliability (BLR) test data for die-level interconnects in integrated circuit (IC) devices is challenging, requiring the design and fabrication of a separate test vehicle die, which is impractical due to resource and expense constraints.
Innovation Solution
Implementing programmable fuse elements in IC devices that allow conversion from a production mode to a test mode, enabling the formation of a stitch chain between die and substrate pads for BLR testing without the need for a separate test vehicle, by selectively coupling and decoupling pads to form links through die-substrate interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate test vehicle die is designed and fabricated for die-level daisy chain testing, then BLR test data for die-level interconnects can be obtained, but the expense and resources involved become impractical
Solution Approach 1:
The production die is designed with dual functionality: it can operate as a standard production device or be reconfigured as a test device. By incorporating programmable fuse elements that can be selectively activated, the same die structure serves both production and testing purposes, eliminating the need for separate test vehicle dies.
Solution Approach 2:
The patent changes the operational parameters of the production die by programmatically altering the state of fuse elements. Through this parameter change, the die transitions from production mode to test mode, enabling daisy chain configuration without requiring a physically different test vehicle die.
2Reliability
If a separate test vehicle die is designed and fabricated for die-level daisy chain testing, then BLR test data for die-level interconnects can be obtained, but the resources involved become impractical
Solution Approach 1:
The production die is designed with dual functionality: it can operate as a standard production device or be reconfigured as a test device. By incorporating programmable fuse elements that can be selectively activated, the same die structure serves both production and testing purposes, eliminating the need for separate test vehicle dies.
3Adaptability or versatility
If production dies are reconfigured for test mode using fuse elements, then BLR testing can be performed without separate test vehicle, but additional circuitry must be integrated into the production die
Solution Approach 1:
The fuse elements are pre-integrated into the production die during fabrication, but remain inactive during normal production operation. The test capability is prepared in advance but only activated when needed, allowing the die to maintain its simple production mode operation while having the option to switch to test mode when required.
Solution Approach 2:
The fuse elements are strategically placed only in specific regions of the die where they are needed for test functionality, rather than uniformly distributing additional circuitry throughout the entire die. This localized approach minimizes the impact on the overall die structure and production functionality.
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
Enables cost-effective and resource-efficient BLR testing of die-level interconnects by repurposing production dies for testing, reducing the complexity and expense of obtaining necessary test data without impacting die size or displacing other circuitry.
Implementation Method 1
programmable fuse elements in IC devices that allow conversion from a production mode to a test mode, enabling the formation of a stitch chain between die and substrate pads
Data Source
AI summary
A method includes fabricating a set of die in a production run, each die comprising a set of pads at a periphery of a top metal layer, a first set of fuse elements, and a second set of fuse elements. Each fuse element of the first set of fuse elements couples a corresponding pad of the set to a corresponding bus when in a conductive state, and each fuse element of the second set couples a corresponding subset of pads of the set together when in a conductive state. The method further includes selecting a subset of the die of the production run for testing, and configuring each die of the subset for testing by placing each fuse element of the first set in a non-conductive state and placing each fuse element of the second set in a conductive state.