Glassless Wafer-Level Optical Sensor Packaging With Protective Dams
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Solution Overview
Problem
Conventional semiconductor packages with glass layers for optical sensors become excessively thick, compromising size constraints in portable electronic devices and introducing optical inefficiencies due to refraction and potential defects, while also increasing manufacturing costs and waste.
Innovation Solution
A glassless wafer-level optical sensor package is developed, featuring dams surrounding the optical sensor to provide protection without a glass layer, utilizing techniques like patterned lithography, polymer deposition, or photo-masked epoxy to form dams, and incorporating a through-silicon via process for circuitry connections, reducing overall thickness and enhancing optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass layer is used to protect the optical sensor, then the sensor is protected from damage, but the package thickness increases excessively and optical inefficiencies occur due to refraction and potential defects
Solution Approach 1:
The patent removes the glass layer from the optical sensor package, extracting the protective function from the traditional glass encapsulation approach. This eliminates the refraction and defect issues associated with glass while reducing package thickness, as the sensor is protected through alternative means such as wafer-level packaging structures and protective coatings applied directly to the sensor surface.
Solution Approach 2:
The patent changes the material parameter from glass to alternative protective materials such as organic passivation layers, inorganic dielectric layers, or composite coating structures. This parameter change eliminates optical refraction issues while providing adequate protection, and allows for thinner package design through advanced material properties and deposition techniques.
2Reliability
If a glass layer is used to protect the optical sensor, then the sensor is protected from damage, but optical performance deteriorates due to refraction and potential defects
Solution Approach 1:
The glass layer is completely removed from the optical path, eliminating the source of refraction and optical defects. The sensor is protected through wafer-level packaging techniques and protective coatings that do not interfere with optical performance, ensuring high illumination intensity and optimal sensor response.
Solution Approach 2:
The protective function traditionally provided by glass is copied and replicated through alternative materials and structures such as thin-film dielectric layers, organic passivation coatings, and wafer-level encapsulation structures. These alternatives provide protection without the optical interference characteristics of glass.
3Reliability
If a glass layer is used in the optical sensor package, then the sensor is protected, but manufacturing costs and waste increase
Solution Approach 1:
The glass layer is removed from the manufacturing process, eliminating the costs associated with glass material, glass bonding, and glass defect management. The patent employs wafer-level packaging processes that use standard semiconductor manufacturing techniques, reducing material costs and simplifying the manufacturing workflow.
Solution Approach 2:
The patent transitions from glass-based packaging to alternative materials such as organic polymers, inorganic dielectrics, or composite structures that can be deposited using standard semiconductor fabrication processes. This parameter change enables cost-effective manufacturing through established process technologies and reduces material waste.
Data Source
AI summary
A glassless wafer-level optical sensor semiconductor package is provided. A method of manufacturing a glassless wafer-level optical sensor package of an example includes: forming one or more dams at least partially surrounding one or more optical sensors on a wafer; supporting the wafer on a carrier substrate via the one or more dams; forming a wafer-level optical sensor integrated circuit for each of the one or more optical sensors on the wafer by: performing a through-silicon via process on the wafer; forming an isolation layer on the wafer; and performing a passivation operation on the wafer; removing the wafer from the carrier substrate; and singulating each wafer-level optical sensor integrated circuit.