Fingerprint Sensor Packaging With Molded IC Impact Protection
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Solution Overview
Problem
Fingerprint recognition devices using wafer level fan-out package processes are prone to damage from external impacts due to exposed driving units and increased manufacturing costs, especially when used in button form factors like smartphone home keys.
Innovation Solution
A fingerprint recognition device with an integrated circuit connected to sensor electrodes via a first and second circuit substrate, protected by a molding layer and reinforced with signal transmission paths and underfill resin, which separates the driving unit from external impacts and simplifies manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If wafer level fan-out package process is used, then manufacturing efficiency is improved, but the driving unit part of the integrated circuit is positioned close to the surface exposed to the outside, making it vulnerable to impact damage
Solution Approach 1:
The patent repositions the driving unit from a surface-level location (2D plane) to an embedded location within the substrate (3D space). The driving unit is placed in a recessed area and covered by a protective layer, transitioning from exposed surface mounting to embedded three-dimensional positioning, thereby protecting it from external impacts while maintaining manufacturing efficiency.
Solution Approach 2:
The patent implements protective structures in advance before the device is subjected to impact. A protective layer is formed over the driving unit, and the driving unit is positioned in a recessed area, creating a cushioning effect that absorbs or mitigates external impacts before they can reach the vulnerable circuit components.
2Adaptability or versatility
If wafer level fan-out package process is used for small area integrated circuits, then device functionality is achieved, but manufacturing cost increases due to decreased I/O relocation efficiency
Solution Approach 1:
The patent applies different structural treatments to different regions of the substrate. The driving unit area receives special protection with recessed positioning and protective layers, while other areas maintain standard fan-out packaging. This localized quality enhancement protects the vulnerable driving unit without unnecessarily complicating the entire manufacturing process, thereby controlling costs while ensuring functionality.
3Speed
If the integrated circuit is exposed to the outside surface, then signal transmission efficiency is improved, but the circuit becomes vulnerable to physical and environmental damage
Solution Approach 1:
The patent introduces a protective layer as an intermediary between the driving unit and the external environment. This protective layer acts as a mediator that allows the driving unit to remain functionally connected (maintaining signal transmission) while physically isolating it from harmful external factors such as moisture, dust, and mechanical impact.
Solution Approach 2:
The driving unit is nested within the substrate structure, specifically positioned in a recessed area and covered by a protective layer. This nested configuration allows the driving unit to be embedded within the overall device structure rather than exposed on the surface, protecting it from environmental factors while maintaining its electrical and functional connections.
Data Source
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AI summary
Disclosed are fingerprint recognition device having an improved structure to enable a driving device of an integrated circuit to have durability, a manufacturing method therefor, and an electronic device. The fingerprint recognition device comprise: an integrated circuit electrically connected to at least one sensor electrode; a first circuit board located at an upper portion of the integrated circuit and provided with the at least one sensor electrode; a second circuit board electrically connected to the first circuit board and located at under the integrated circuit; a molding layer provided under the first circuit board to surround the integrated circuit so as to protect the integrated circuit from the outside; and a connection part electrically connecting the first circuit board and the second circuit board.