BGA Structural Elements for Solder Joint Shock Resilience
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Solution Overview
Problem
Semiconductor devices are prone to interface cracking at solder ball connections due to mechanical impact or temperature fluctuations, leading to potential open circuits and device failure.
Innovation Solution
Incorporation of structural elements, such as stiff copper wires or metal walls, at the interface of the ball grid array between the semiconductor device and the printed circuit board to absorb shock and relieve stress from solder ball joints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If semiconductor devices are mounted on substrates in grid patterns, then device assembly and connectivity are achieved, but the solder joints become vulnerable to cracking under mechanical impact and temperature fluctuations
Solution Approach 1:
The patent applies beforehand cushioning by incorporating shock-absorbing structural elements (such as compliant substrates, damping materials, or flexible interconnects) between the semiconductor device and substrate before assembly. These elements are designed to absorb mechanical impact and mitigate thermal stress before they can reach the solder joints, thereby preventing crack initiation and maintaining solder joint reliability under environmental stress
Solution Approach 2:
The patent applies parameter changes by modifying the mechanical and thermal properties of the interface structure between the semiconductor device and substrate. This includes changing the stiffness, damping characteristics, or thermal expansion coefficients of intermediate layers or mounting structures to better match the solder joints and reduce stress concentration, thereby improving resistance to mechanical impact and temperature fluctuations
2Productivity
If corner and edge solder joints are positioned to maximize device utilization, then manufacturing efficiency is improved, but these locations become critical points for crack initiation under shock loading
Solution Approach 1:
The patent applies local quality by providing enhanced protection specifically at the corner and edge regions where solder joints are most vulnerable to cracking. This may include adding localized reinforcement structures, increasing the size or strength of corner/edge solder joints, or applying protective coatings only at these critical locations, thereby maintaining overall assembly efficiency while selectively strengthening the most vulnerable areas
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 structural elements enhance the resilience of semiconductor devices by reducing the likelihood of crack initiation at corner and edge solder joints, thereby increasing solder joint reliability, yield, and extending the life of the semiconductor package.
Implementation Method 1
structural elements, such as stiff copper wires or metal walls, at the interface of the ball grid array between the semiconductor device and the printed circuit board to absorb shock and relieve stress from solder ball joints
Implementation Method 2
structural elements... to absorb shock and relieve stress from solder ball joints
Data Source
AI summary
A semiconductor package assembly includes a first mounting surface of a package substrate that faces a second mounting surface of a printed circuit board. A first structural element bond pad is mounted to the first mounting surface. A second structural element bond pad is mounted to the second mounting surface, and the first and second structural element bond pads are aligned with each other. A structural element is interconnected with a first solder joint to the first structural element bond pad and interconnected with a second solder joint to the second structural element bond pad. The structural element extends between the first and second structural element bond pads to absorb mechanical shock when a compressive force pushes one of the first and second mounting surfaces toward the other.