Circuit Carrier Access Opening for Underfilling Small Pitch Components
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Solution Overview
Problem
Electronic components with small pitch spacings between contact connections pose a challenge for reliable underfill introduction, as existing methods risk damaging conductor tracks or are mechanically obstructed, compromising electrical functionality.
Innovation Solution
A contact arrangement with an access opening in the circuit carrier allows for the introduction of underfill material, either by pressure or suction, where a non-electrically contacted redundant connection is partially covered, enabling filling without impeding the flow of material and maintaining electrical functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an access opening is provided between contact terminals for underfill introduction, then the underfill can be introduced into the spacer gap, but the pitch between contact terminals must be large enough to accommodate the opening
Solution Approach 1:
The invention extracts the underfill introduction function from the space between contact terminals by providing a separate access opening in the circuit carrier. This allows the underfill to be introduced through a dedicated opening rather than relying on the spacing between contact terminals, thereby resolving the contradiction between needing an access opening and maintaining small pitch dimensions.
Solution Approach 2:
The circuit carrier acts as an intermediary by providing an access opening through its structure. This mediator enables the underfill introduction process without requiring direct access between contact terminals, allowing small pitch components to be underfilled reliably through the circuit carrier's opening rather than through the component's contact terminal spacing.
2Ease of manufacture
If underfill is introduced laterally along the edge of the component, then capillary forces can draw the underfill under the component, but this method cannot be used with very small pitch components where no opening can be formed
Solution Approach 1:
The invention changes the dimension of underfill introduction from lateral (horizontal) flow along component edges to vertical flow through the circuit carrier. By introducing underfill from below through an access opening in the circuit carrier, the process works for small pitch components where lateral introduction between contact terminals is not feasible.
Solution Approach 2:
The circuit carrier serves as an intermediary structure that enables underfill introduction for small pitch components. The access opening in the circuit carrier provides a pathway for underfill to reach the spacer gap without requiring lateral flow between closely spaced contact terminals, thereby maintaining reliability for small pitch components.
3Reliability
If conductor track structures are routed via an opening for electrical contacting, then contact terminals can be electrically connected, but introducing underfill laterally past the conductor track risks damaging it
Solution Approach 1:
The invention segments the functions of electrical contacting and underfill introduction by providing separate structures: conductor tracks for electrical contact and a dedicated access opening for underfill introduction. This segmentation allows underfill to be introduced vertically through the access opening without requiring lateral flow that would expose conductor tracks to damage risks.
Solution Approach 2:
The access opening in the circuit carrier acts as an intermediary pathway for underfill introduction, separating the underfill flow path from the conductor track structures. This intermediary structure enables underfill to reach the spacer gap without contacting or potentially damaging the conductor tracks that provide electrical connectivity.
4Productivity
If electronic components with very small pitch are used, then component density increases, but it becomes impossible to provide openings between contact terminals for underfill introduction
Solution Approach 1:
The invention extracts the underfill introduction function from the component-level contact terminal spacing and relocates it to the circuit carrier level. This allows high-density component placement with small pitch while maintaining underfill introduction capability through the circuit carrier's access opening, which is independent of component pitch dimensions.
Solution Approach 2:
The invention resolves the density-reliability contradiction by changing the dimension of underfill access from the horizontal plane (between contact terminals) to the vertical dimension (through the circuit carrier). This dimensional shift enables both high component density with small pitch and reliable underfill introduction through the circuit carrier's access opening.
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 solution allows for reliable underfilling of components with close contact connections, ensuring the electrical integrity and mechanical reliability of electronic components, even with very small pitch spacings, by guiding the filling material past the contact connections without damaging them.
Implementation Method 1
Common underfill processes use capillary forces to suck the underfill dispensed laterally along the edge of the component under the component.
Implementation Method 2
An alternative form of underfilling is to apply the material under pressure through a hole in the circuit board between external contact terminals of the electronic component
Implementation Method 3
an opening in the circuit carrier below the contacted electronic component is used to facilitate the suction of an underfill into the spacer gap between the circuit carrier and the electronic component by applying a vacuum device
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
The invention relates to a contact arrangement comprising a circuit carrier with an upper side and a lower side and at least one electronic component, the circuit carrier comprising at least contact points on the upper side, which are in electrical contact with contact connections of the electronic component. Said contact arrangement also comprises a filler material that fills a gap between the upper side of the circuit carrier and the electronic component, the circuit carrier comprising an access opening for introducing the filler material. The electronic component comprises an arrangement of the contact connections on a component side facing the upper side of the circuit carrier, a connection surface being at least partially covered with precisely one of three adjacent contact connections in a vertical projection on the upper side of the access opening.