Semiconductor Package Cover Layout to Prevent Sensor Adhesive Bleed
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Solution Overview
Problem
The reliability of semiconductor packages, particularly those with image sensor chips, is compromised due to adhesive bleeding onto active or non-active areas during packaging, leading to optical failures and reduced performance.
Innovation Solution
A semiconductor package design featuring a protective cover with a cap adhesive region on its bottom surface, where the cover adhesive forms a hermetically sealed cavity over the sensor region, preventing adhesive bleed and enhancing package reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesive is used to attach the cover to the die, then the cover is securely attached, but adhesive bleeds to the active or sensor area causing optical failure
Solution Approach 1:
The bottom surface of the protective cover is segmented into distinct functional regions: a cap adhesive region for secure attachment and a sensor region that remains free of adhesive. This segmentation prevents adhesive bleed to the sensor area while maintaining strong cover attachment through the dedicated adhesive region.
Solution Approach 2:
Different regions of the cover's bottom surface are given different properties: the cap adhesive region has adhesive applied to it for strong bonding, while the sensor region maintains optical clarity and freedom from adhesive contamination. This local differentiation resolves the contradiction between attachment strength and optical reliability.
2Stability of the object's composition
If adhesive is used to attach the cover, then the cover is fixed in place, but the adhesive bleeds over the exposed top surface during encapsulation
Solution Approach 1:
The cover's bottom surface is divided into a cap adhesive region where adhesive is confined and a sensor region that remains protected from adhesive bleed. This segmentation contains the adhesive's harmful bleeding effect to a specific area while protecting the sensor region.
Solution Approach 2:
The adhesive's natural tendency to bleed is converted into a benefit by directing it away from the sensor area. The cap adhesive region is designed to contain and control adhesive placement, transforming the potential harm of adhesive bleed into a controlled bonding mechanism that secures the cover without contaminating the sensor region.
3Object-affected harmful factors
If a transparent cover is attached over the sensor area, then the sensor is protected, but adhesive contamination increases the risk of optical failure
Solution Approach 1:
The protective cover is segmented into a sensor region that provides optical access and protection to the sensor area, and a cap adhesive region that handles the attachment function. This segmentation allows the sensor region to remain free of adhesive contamination while still providing protection, thus maintaining optical performance reliability.
Solution Approach 2:
The cover exhibits local quality differentiation where the sensor region maintains optical transparency and freedom from contamination for optimal light transmission, while the cap adhesive region provides the necessary mechanical bonding. This local differentiation ensures both sensor protection and optical reliability.
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 effectively prevents adhesive bleed to undesired areas, stabilizes wire bonds, and reduces package footprint, thereby improving the reliability and performance of semiconductor packages by forming a sealed cavity over the sensor region.
Implementation Method 1
A cover adhesive is disposed on the cap adhesive region on the bottom surface of the protective cover. The protective cover is attached onto the die by the cover adhesive
Data Source
AI summary
A semiconductor package and a method of manufacturing thereof is disclosed. The package includes a package substrate having a die attach region with a die attached thereto. A protective cover with a cover adhesive is disposed over a sensor region of the die and attached to the die by the cover adhesive. The cover adhesive is disposed in a cap bonding region of the protective cover.