Fan-out Sensor Package with Embedded Optical Lens
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Solution Overview
Problem
Existing optical-type fingerprint sensor packages face challenges with complexity, increased size and thickness due to bonding wires, warpage issues, and decreased fingerprint sensing sensitivity, making them difficult to integrate with infrared cut filters and metal shields.
Innovation Solution
A fan-out sensor package design featuring a sensor chip in a through-hole of a first connection member with a wiring layer, a second connection member with a redistribution layer to connect the sensor chip's pads to the wiring layer, and an encapsulant that exposes a portion of the optical lens, reducing warpage and improving optical recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding wires and separate optical lens are used in the sensor package, then the sensor chip can be connected to the BGA substrate, but the structure becomes complicated and the package size and thickness increase
Solution Approach 1:
The patent combines the optical lens with the sensor chip into an integrated structure, eliminating the need for separate bonding wires and reducing structural complexity. The lens is formed directly on the sensor chip surface, merging two previously separate components into one unified element that maintains connection reliability while simplifying the overall package structure.
Solution Approach 2:
The patent embeds the optical lens within the sensor chip structure itself, nesting the optical component inside the sensor assembly. This nested configuration allows the lens to be integrated into the chip's active area without requiring external mounting, thereby reducing package thickness and eliminating complex interconnections while maintaining functional reliability.
2Reliability
If bonding wires and separate optical lens are used in the sensor package, then the sensor chip can be connected to the BGA substrate, but the package thickness increases
Solution Approach 1:
The patent merges the optical lens with the sensor chip into a single integrated component, eliminating the need for separate bonding wire assemblies and reducing the overall package thickness. The lens is formed directly on the chip surface, consolidating vertical space and enabling thinner package profiles while maintaining connection integrity.
Solution Approach 2:
The patent extracts and eliminates the bonding wires from the package structure by integrating the optical lens directly onto the sensor chip. This removal of unnecessary intermediate components reduces the vertical distance required for connections, thereby decreasing package thickness while preserving electrical and optical connection reliability.
3Manufacturing precision
If a complicated molding process is used to control molding thickness, then the package can be manufactured, but the manufacturing complexity increases
Solution Approach 1:
The patent performs preliminary formation of the optical lens directly on the sensor chip before the molding process. By pre-integrating the lens into the chip structure, the subsequent molding process only needs to encapsulate the existing assembly, significantly simplifying thickness control and reducing molding process complexity while maintaining precise dimensional accuracy.
Solution Approach 2:
The patent combines the lens formation and sensor chip fabrication into a single integrated manufacturing step. This merging of processes eliminates the need for complex multi-stage molding operations to accommodate separate lens components, thereby simplifying the overall manufacturing process while achieving precise thickness control through unified process parameters.
4Ease of manufacture
If an asymmetrical structure is used in the sensor package, then the package can be manufactured, but warpage occurs and fingerprint sensing sensitivity decreases
Solution Approach 1:
The patent intentionally introduces asymmetrical compensation structures into the package design to counterbalance the inherent asymmetry from the sensor chip and lens integration. By strategically placing counterweights or support structures on the opposite side of the asymmetrical components, the overall package achieves warpage-free assembly while maintaining manufacturability and preserving fingerprint sensing sensitivity.
Solution Approach 2:
The patent applies counterweight structures to balance the asymmetrical mass distribution caused by the integrated lens and sensor chip. These counterweight elements are positioned to create opposing moments that neutralize warpage forces, allowing the package to be manufactured with asymmetrical components while maintaining planarity and sensing performance.
5Reliability
If the optical recognition region is opened to improve recognition rate, then the optical performance improves, but the region becomes vulnerable to impact damage
Solution Approach 1:
The patent covers the optical recognition region with a transparent protective film or shell that is optically transparent to allow light transmission for fingerprint recognition. This thin film barrier protects the exposed optical region from impact damage while maintaining optical performance, effectively shielding the vulnerable area without compromising the recognition rate.
Solution Approach 2:
The patent applies a protective coating or cushioning layer over the optical recognition region before final assembly. This pre-applied protective layer acts as a shock-absorbing barrier that prevents impact damage to the exposed optical surfaces while allowing light transmission, thereby protecting the vulnerable region without affecting optical recognition performance.
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 design results in a subminiature, ultra-thin package with enhanced optical recognition rates, reduced warpage, and protection against impact, facilitating easier integration with display panels and improved fingerprint sensing sensitivity.
Implementation Method 1
an optical lens disposed in the through-hole and attached to the active surface of the sensor chip
Data Source
AI summary
A fan-out sensor package includes: a first connection member having a through-hole and including a first wiring layer; a sensor chip disposed in the through-hole; an optical lens disposed in the through-hole and attached to the sensor chip; an encapsulant encapsulating at least portions of the first connection member, the sensor chip, and the optical lens; and a second connection member including a first insulating layer disposed on the first connection member, the sensor chip, and the optical lens, a redistribution layer disposed on the first insulating layer, and a second insulating layer disposed on the first insulating layer and covering the redistribution layer. The redistribution layer electrically connects the first wiring layer and the connection pads, the first insulating layer has a cavity exposing at least a portion of one surface of the optical lens, and one side of the cavity is closed by the second insulating layer.