Semiconductor Package Wire Support for PCB Crack Prevention
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Solution Overview
Problem
Existing semiconductor devices face reliability issues due to cracking of printed boards caused by thermal expansion and contraction of sealing materials, which compromises the device's stability under stress and vibration.
Innovation Solution
A semiconductor device design where wires are curved upward and contact the back surface of the printed board, alleviating stress on signal terminals and preventing cracking, while the sealing material is adjusted to contact the printed board, enhancing the device's reliability without requiring precise board dimensions or assembly methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the printed board is pressed with the protrusion of the lid plate to contact the support base, then the printed board is supported and positioned, but the protrusion acts as a force point causing cracking when sealing material expands or contracts due to temperature change
Solution Approach 1:
A resin layer is introduced as an intermediary between the protrusion and the printed board. This resin layer distributes the pressing force over a larger area, preventing stress concentration at the protrusion contact point. The resin acts as a compliant mediator that accommodates thermal expansion and contraction of the sealing material without transmitting concentrated forces to the printed board, thereby preventing cracks while maintaining support and positioning functions.
2Stress or pressure
If the protrusion presses the printed board to alleviate stress on solder joints, then stress on signal terminal is reduced, but the printed board between protrusion and support base may be cracked
Solution Approach 1:
The resin layer serves as a stress-distributing intermediary between the protrusion and the printed board. It allows the protrusion to exert pressing force for stress relief on solder joints while simultaneously preventing stress concentration that would cause cracking in the printed board. The resin's compliant nature enables it to accommodate thermal variations without transmitting damaging forces to the board.
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 suppresses cracking of the printed board, improving the semiconductor device's reliability by distributing stress and allowing for flexible manufacturing processes, and adjusting the sealing material's position to support the board effectively.
Implementation Method 1
When stress is applied to the signal terminal connected to the printed board due to the vibration of the semiconductor device, the stress applied to the signal terminal is alleviated by the wire in contact with the back surface of the printed board.
Implementation Method 2
when the sealing material in the case expands or contracts due to a temperature change
Data Source
AI summary
A semiconductor device includes a semiconductor element, a case having an opening and accommodating the semiconductor element, a signal terminal provided on the inner wall of the case, a printed board disposed above the semiconductor element in the case by the signal terminal, and a lid that closes the opening of the case. The semiconductor element and the signal terminal are electrically connected by the wire. The wire is curved upward, and the top portion of the wire is in contact with the back surface of the printed board.