Ball Grid Array Solder Strain Detection via Impedance Monitoring
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Solution Overview
Problem
Information handling systems face failures due to invisible solder cracks on circuit boards caused by mechanical strain, particularly in ball grid array integrated circuits, which can lead to operational issues when the systems are lifted or exposed to certain temperature ranges.
Innovation Solution
An information handling system with a management controller that detects impedance discontinuities in solder balls by outputting a known signal and comparing it with the received signal, allowing for the identification of strain-induced open circuits or cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional manufacturing and handling processes are used for circuit boards, then production efficiency and handling ease are maintained, but solder cracks occur due to mechanical strain causing system failures
Solution Approach 1:
The patent applies preliminary action by implementing strain sensors and monitoring systems before solder cracks actually occur. The system proactively detects mechanical strain on the circuit board during handling and manufacturing processes, allowing preventive measures to be taken before the strain causes visible damage or system failure.
Solution Approach 2:
The patent implements feedback mechanisms through strain sensors that continuously monitor mechanical stress on the circuit board and provide real-time data to the management controller. This feedback loop enables the system to track strain accumulation and alert operators or automatically adjust handling procedures to prevent solder joint failure.
2Reliability
If mechanical strain monitoring is implemented to detect solder cracks, then system reliability improves, but device complexity increases due to additional sensors and monitoring systems
Solution Approach 1:
The patent applies universality by designing a management controller that performs multiple functions: it manages overall system operations, processes strain sensor data, detects impedance changes, and coordinates preventive actions. This multi-functional approach consolidates monitoring capabilities into existing infrastructure rather than adding separate dedicated systems, thereby reducing overall complexity.
Solution Approach 2:
The system applies self-service by using the circuit board's existing electrical infrastructure (power and data lines) to also carry strain monitoring functions. The same management controller that manages normal system operations is also used to process strain data and detect solder issues, eliminating the need for separate dedicated monitoring hardware and reducing system complexity.
3Manufacturing precision
If impedance detection methods are used to identify open circuits, then manufacturing precision improves, but measurement precision may be affected by signal interference
Solution Approach 1:
The patent applies the intermediary principle by introducing strain sensors as intermediate detection elements between the mechanical strain and the electrical impedance measurement. These sensors convert mechanical stress into electrical signals that can be processed by the management controller, providing a clearer and more reliable indication of solder joint status than direct impedance measurement alone.
Solution Approach 2:
The patent applies mechanics substitution by replacing direct mechanical inspection methods with electrical impedance detection. Instead of physically examining solder joints for cracks, the system uses electrical measurements to detect changes in impedance that indicate the presence of solder cracks or open circuits, enabling non-invasive and more precise detection.
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
The solution effectively reduces the risk of system failures by detecting mechanical strain and impedance discontinuities, enabling timely notification and remedial actions to prevent damage to the circuit board.
Implementation Method 1
detect whether an impedance discontinuity has occurred with respect to one or both of the first solder ball and the second solder ball
Data Source
AI summary
An information handling system may include a circuit board, an integrated circuit package mounted on the circuit board, the integrated circuit package comprising: a plurality of solder balls for electrically coupling the integrated circuit package to the circuit board, the plurality of solder balls comprising a first solder ball and a second solder ball, an internal electrical coupling coupled between the first solder ball and the second solder ball, and a management controller electrically coupled to the internal electrical coupling, the first solder ball, and the second solder ball, and configured to provide out-of-band management facilities for management of the information handling system, the management controller further configured to detect whether an impedance discontinuity has occurred with respect to one or both of the first solder ball and the second solder ball.