Circuit Board Inspection Path for Capacitor Tombstone Detection
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Solution Overview
Problem
The occurrence of physical poor connections, such as tombstones and detachments, between capacitors and wiring boards in semiconductor devices during high-speed operation is a significant issue.
Innovation Solution
A circuit board design with an inspection path that includes separated ends of wirings between electrode lands, allowing for efficient detection of physical connections using a daisy chain method, ensuring all capacitors are connected to the wiring board, and a conductor between external electrodes and lands to enhance connection strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If capacitors are mounted on wiring boards for noise countermeasure during high-speed operation, then noise suppression is improved, but physical poor connections (tombstones, detachments) occur between capacitors and wiring boards
Solution Approach 1:
The patent applies preliminary action by forming inspection paths on the wiring board before mounting capacitors. These inspection paths include separated first and second wirings that will later be connected through capacitor electrodes. By preparing the inspection infrastructure in advance, the patent enables subsequent detection of proper capacitor mounting, preventing undetected poor connections from compromising reliability.
Solution Approach 2:
The patent uses inspection paths as an intermediary mechanism between the capacitor mounting process and quality assurance. The separated first and second wirings act as mediators that, when connected through properly mounted capacitor electrodes, provide measurable electrical continuity. This intermediary inspection system detects tombstones and detachments that would otherwise go unnoticed.
2Productivity
If traditional capacitor mounting inspection is used, then manufacturing process is simple, but detection of physical poor connections is difficult and time-consuming
Solution Approach 1:
The patent replaces manual or complex mechanical inspection methods with electrical measurement. By substituting physical inspection with electrical resistance measurements through the inspection paths, the system achieves faster, more automated detection of poor connections. This substitution dramatically improves inspection efficiency while reducing the difficulty of detecting tombstones and detachments.
Solution Approach 2:
The inspection paths are designed to be self-testing through electrical continuity measurement. The separated first and second wirings automatically form a test circuit when capacitors are mounted, allowing the system to self-diagnose mounting quality without external intervention. This self-service approach enables rapid detection of physical poor connections across all capacitors simultaneously.
3Measurement precision
If inspection paths with separated first and second wirings are formed between electrodes, then detection of physical connections is improved, but device complexity increases
Solution Approach 1:
The inspection paths serve multiple functions: they act as both signal transmission conduits and quality inspection circuits. The same first and second wirings that carry electrical signals also serve as measurement paths for detecting capacitor mounting quality. This multi-functionality reduces the need for separate dedicated test circuits, thereby limiting the increase in device complexity while maintaining high measurement precision.
Solution Approach 2:
The patent implements partial inspection action by focusing measurement only on the critical connection points between capacitors and wiring boards. Rather than inspecting the entire circuit board, the inspection paths are strategically placed only where capacitor connections occur. This partial approach achieves sufficient detection precision for quality control without unnecessarily increasing overall device complexity.
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
This design enables efficient detection of poor connections in capacitors, improving yield and preventing capacitors from falling off, thus enhancing the reliability and efficiency of semiconductor devices.
Implementation Method 1
an inspection path is formed. The inspection path includes a first wiring including one end between the pair of electrodes, and a second wiring including one end between the pair of electrodes
Data Source
AI summary
A circuit board is a wiring board frame in which a plurality of wiring boards in each of which a pair of lands electrically connected to a capacitor are formed on a first surface are arranged side by side. In the wiring board frame, an inspection path is formed. The inspection path passes between the pair of lands provided on each of the plurality of wiring boards. The inspection path includes a first wiring including one end between the pair of lands, and a second wiring including one end between the pair of lands, and the one end of the first wiring and the one end of the second wiring are formed to be separated from each other.