Reinforced Semiconductor Corners for PCB Solder Ball Reliability
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Solution Overview
Problem
Solder balls at the corners of semiconductor devices are prone to dislodging due to mechanical and thermal stresses, leading to board level reliability (BLR) failures and loss of electrical connectivity.
Innovation Solution
Incorporating capacitors at the corners of semiconductor devices, which provide both electrical and mechanical support by embedding support via portions within solder end posts during the reflow process, creating a robust mechanical bond with the printed circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder balls are used at corner positions for electrical connection, then electrical connectivity is achieved, but mechanical reliability deteriorates due to dislodging under thermal and impact stress
Solution Approach 1:
The patent applies preliminary action by pre-forming support vias with enlarged portions at corner positions before mounting the semiconductor device. These enlarged portions are prepared in advance to receive and mechanically interlock with capacitor components, creating a reinforced structure that prevents solder ball dislodging during subsequent thermal cycling and impact events.
Solution Approach 2:
The patent employs composite materials by combining multiple components at corner positions: the substrate, solder balls, support vias with enlarged portions, and capacitor components. This composite structure integrates electrical connection functions (solder balls) with mechanical reinforcement functions (capacitors and enlarged via portions), creating a multi-functional corner structure that simultaneously provides electrical connectivity and enhanced mechanical strength.
2Strength
If corner positions are reinforced with additional structures, then mechanical strength is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the capacitor components to serve dual functions: electrical function (providing decoupling capacitance for power stability) and mechanical function (acting as reinforcement structures that mechanically interlock with the enlarged via portions). This multi-functionality allows corner reinforcement without adding dedicated mechanical support components, thereby reducing overall device complexity.
Solution Approach 2:
The patent merges the electrical connection function and mechanical support function into a single integrated corner structure. The capacitor components are positioned to simultaneously provide electrical capacitance and mechanical reinforcement through interference fit with the enlarged via portions, eliminating the need for separate mechanical support structures and simplifying the overall device design.
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
Prevents solder ball dislodging, enhances electrical connectivity, and improves thermal management by providing structural reinforcement and heat dissipation.
Implementation Method 1
embedding support via portions within solder end posts during the reflow process, creating a robust mechanical bond
Data Source
AI summary
A semiconductor device is mounted to a printed circuit board by one or more capacitor. The capacitors provide a dual function of electrically and mechanically supporting the semiconductor device. Multiple semiconductor devices are formed on a panel of substrates. Support vias are formed in the saw street between adjacent substrate instances, at the corners of each substrate instance. Portions of these support vias remain at the corners of each semiconductor device when the devices are singulated from the panel. These portions of the support vias are used to bond the semiconductor devices to the capacitors on the printed circuit board.