Semiconductor Package Dummy Pattern Layout for Warpage Reliability
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Solution Overview
Problem
The miniaturization and slimming of electronic devices lead to increased warpage in multilayer printed circuit boards, which can cause malfunction due to open ball contacts between semiconductor chips and the substrate.
Innovation Solution
A semiconductor package design that includes a first substrate with a circuit pattern and dummy patterns, a solder resist layer, and an underfill material layer that wraps around solder balls, effectively preventing cracks from spreading and improving connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the multilayer printed circuit board is made thinner to achieve miniaturization and slimness, then the electronic device becomes more compact and sleek, but the warpage of the board increases which can cause open ball contacts and malfunction
Solution Approach 1:
The invention introduces dummy patterns as separate structural elements that are not electrically connected to the circuit pattern but serve to segment and reinforce the substrate structure. These dummy patterns are distributed across the substrate to provide localized support and reduce overall warpage, thereby maintaining connection reliability in thinner boards
Solution Approach 2:
The dummy patterns are strategically placed in specific regions of the substrate where warpage is most likely to occur. By providing localized structural reinforcement rather than uniform thickening, the board maintains its overall thin profile while achieving sufficient rigidity to prevent open ball contacts
2Reliability
If dummy patterns are added to the substrate to prevent warpage, then connection reliability improves, but the device complexity increases due to additional patterns
Solution Approach 1:
The dummy patterns are electrically isolated from the circuit pattern by being covered with solder resist material. This extraction of the dummy patterns from the electrical circuit allows them to serve purely structural functions without adding complexity to the electrical design or requiring additional electrical connections
Solution Approach 2:
The solder resist layer serves as an intermediary that covers the dummy patterns, preventing them from being part of the electrical circuit while still allowing them to provide structural support. This mediator allows the dummy patterns to fulfill their warpage prevention function without increasing electrical circuit complexity
Data Source
AI summary
A semiconductor package includes a first substrate including a circuit pattern and a dummy pattern on an upper face of the first substrate, a solder ball, a second substrate on the first substrate, and an underfill material layer between the first and second substrates. The underfill material layer wraps around the solder ball. The dummy pattern is not electrically connected to the circuit pattern. The first substrate includes a solder resist layer on the circuit pattern and the dummy pattern. The solder resist layer includes a first opening for exposing at least a part of the circuit pattern. The solder ball is in the first opening and electrically insulated from the dummy pattern by the solder resist layer. The second substrate is electrically connected to the first substrate by the solder ball. The second substrate is electrically insulated from the dummy pattern by the solder resist layer.