Fingerprint Sensor Package With Through-Hole Nesting
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Solution Overview
Problem
Fingerprint sensor packages face challenges in achieving reliable and sensitive fingerprint recognition while minimizing size and thickness, while also ensuring economic feasibility and preventing financial losses due to theft or loss of smart cards.
Innovation Solution
A fingerprint sensor package design featuring a first substrate with a core insulating layer, through-hole, bonding pads, and a second substrate with sensing patterns, connected by conductive wires and a controller chip, is integrated into a smart card, enhancing reliability and sensitivity while maintaining a thin profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fingerprint sensor package uses a through-hole structure with sensing patterns disposed inside, then the sensitivity and reliability of fingerprint recognition is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The second substrate containing sensing patterns is disposed inside the through-hole of the first substrate, creating a nested structure where one component is embedded within another. This nesting approach improves fingerprint recognition reliability by positioning sensing patterns closer to the fingerprint contact surface while managing the complexity through integrated design
Solution Approach 2:
The sensing patterns are arranged in multiple directions (first direction and second direction intersecting at approximately 90 degrees) within the through-hole space, utilizing three-dimensional positioning to enhance sensing capability while efficiently using the available volume
2Reliability
If the fingerprint sensor package uses a through-hole structure with sensing patterns disposed inside, then the sensitivity and reliability of fingerprint recognition is improved, but the manufacturing cost increases
Solution Approach 1:
The first substrate, second substrate, and molding layer are combined into an integrated package structure where the molding layer simultaneously fills the through-hole, covers the second substrate, and provides external connection interfaces. This merging reduces the number of separate manufacturing steps and lowers overall production cost while maintaining improved fingerprint recognition reliability
3Volume of moving object
If the fingerprint sensor package reduces overall size and thickness, then the product compactness is improved, but the sensitivity and reliability of fingerprint recognition may deteriorate
Solution Approach 1:
By nesting the second substrate with sensing patterns inside the through-hole of the first substrate, the design achieves compact volume while maintaining the sensing patterns at an optimal position for fingerprint recognition, thus improving package compactness without sacrificing reliability
Solution Approach 2:
The sensing patterns extend in multiple directions (first and second directions) within the limited through-hole space, maximizing the sensing area and reliability within a compact footprint, achieving both small size and high reliability
4Strength
If the molding layer covers the first bonding pad and fills the through-hole, then the structural integrity and protection are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The molding layer performs multiple functions simultaneously: it fills the through-hole to provide structural support, covers the second substrate for protection, and positions the external connection pad. This multi-functionality improves structural integrity while the integrated design approach helps manage manufacturing precision requirements
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 solution improves the reliability and sensitivity of fingerprint recognition, reduces the overall size and thickness of the fingerprint sensor package, and enhances the security of smart cards by preventing unauthorized access, thus addressing the financial risks associated with theft or loss.
Implementation Method 1
a conductive wire connecting the first bonding pad and the second bonding pad
Implementation Method 2
a plurality of first sensing patterns spaced apart from each other in a first direction and extending in a second direction intersecting the first direction, a plurality of second sensing patterns spaced apart from each other in the second direction and extending in the first direction
Data Source
AI summary
A fingerprint sensor package includes a first substrate having a core insulating layer with a first surface and a second surface, and a through-hole passing through the first surface and the second surface, a first bonding pad disposed on the second surface of the core insulating layer, and an external connection pad, a second substrate disposed in the through-hole of the core insulating layer and including a plurality of first sensing patterns, a plurality of second sensing patterns, and a second bonding pad, a conductive wire connecting the first bonding pad and the second bonding pad to each other, a controller chip disposed on the second substrate, and a molding layer disposed on the second surface of the core insulating layer, filling the through-hole, covering the second substrate and the first bonding pad, and spaced apart from the external connection pad.