Optical Sensor Package Layout to Block Cross-Talk and Moisture
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Solution Overview
Problem
Optical sensor packages in modern electronic devices face challenges such as limited space, cross-talk issues, and performance degradation due to moisture absorption in clear mold structures, with existing solutions failing to address these problems effectively.
Innovation Solution
A sensor package design where an optical sensor die is embedded in a non-transparent molding compound, with only its active surface exposed, and features backside contacts connected via conductive vias and redistribution layers, eliminating the need for a clear mold and reducing package size while preventing cross-talk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a clear mold structure is used for protection of the active components, then the sensor package is protected, but performance and reliability degradation occurs due to moisture absorption and permeation
Solution Approach 1:
The patent changes the optical property of the mold compound from transparent to opaque (black or dark-colored). This opaque molding compound prevents light transmission while providing protection, eliminating the moisture absorption issues associated with clear molds and preventing cross-talk between adjacent sensor packages.
2Strength
If a clear mold structure is used, then protection is provided, but cross-talk occurs between adjacent sensor packages
Solution Approach 1:
The opaque (black or dark-colored) molding compound blocks light transmission between adjacent sensor packages, preventing cross-talk while maintaining mechanical protection of the active components.
3Volume of moving object
If the package size is reduced, then space efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent integrates the mold compound to serve multiple functions simultaneously: mechanical protection, optical isolation (preventing cross-talk), and moisture barrier. This consolidation of functions into a single component achieves compact packaging while managing complexity through functional integration.
Solution Approach 2:
The use of opaque molding compound combines mechanical protection properties with optical blocking properties, creating a composite material solution that achieves multiple goals (protection, cross-talk prevention, moisture barrier) in a single material system, thereby reducing overall package complexity.
Data Source
AI summary
A sensor package includes an encapsulation body formed from a mold compound having a front side and a back side opposite the front side, an optical sensor die embedded within the encapsulation body on the front side such that an active surface of the optical sensor die is uncovered by the encapsulation body, and a conductive via that extends from the front side to the back side through the encapsulation body. The sensor package also includes a topside redistribution layer arranged on the front side, the topside redistribution layer electrically connecting the optical sensor die to the conductive via, a connection element arranged on the back side for electrically connecting the sensor package to an integrated circuit device, and a backside redistribution layer arranged on the back side. The backside redistribution layer electrically connects the connection element to the conductive via.