Semiconductor Package Cavity Interlocks Against Encapsulant Delamination
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Solution Overview
Problem
Conventional semiconductor packages for image sensor chips experience delamination of the encapsulant from the package substrate, leading to reliability issues.
Innovation Solution
The method involves forming cavity interlocks within the encapsulation region of the package substrate to enhance adhesion, depositing an encapsulant with a step profile, and attaching a protective cover to create a hermetic cavity structure with a predetermined height over the die, preventing delamination and ensuring package reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional encapsulant structure is used to form a cavity over the die, then the package structure is simple and easy to manufacture, but delamination occurs between the encapsulant and package substrate, reducing reliability
Solution Approach 1:
The encapsulant structure is segmented into multiple regions with different heights, creating a stepped configuration. The first encapsulant region has a first height and the second encapsulant region has a second height different from the first height. This segmentation allows the encapsulant to better conform to the package substrate surface, improving adhesion and preventing delamination while maintaining manufacturing feasibility.
Solution Approach 2:
Different regions of the encapsulant are given different local properties through the stepped structure. The first encapsulant region and second encapsulant region have different heights, creating localized variations in the encapsulant structure. This local quality differentiation enhances adhesion at critical interfaces without requiring complete structural redesign, thus improving reliability while controlling complexity.
2Reliability
If the encapsulant is deposited to fully cover the encapsulation region, then adhesion area is maximized, but the encapsulant may delaminate from the package substrate
Solution Approach 1:
The encapsulant is divided into separate regions (first encapsulant region and second encapsulant region) with different heights. This segmentation creates a stepped structure that maintains adequate adhesion area while preventing the continuous stress that leads to delamination. The segmented structure allows each region to independently adhere to the substrate without compromising overall structural stability.
Solution Approach 2:
The encapsulant structure transitions from a two-dimensional planar coverage to a three-dimensional stepped structure by varying the height in the vertical dimension. The first encapsulant region and second encapsulant region have different heights, creating a multi-level configuration that improves adhesion while maintaining structural integrity through vertical differentiation rather than horizontal expansion alone.
Data Source
AI summary
A semiconductor package and method for forming thereof are disclosed. The package includes a package substrate having a die region with a die attached thereto. An encapsulant is disposed to cover encapsulation region of the package substrate. A protective cover is disposed over the die and attached to the encapsulant by a cover adhesive. The protective cover is supported by a lower portion of step shaped inner encapsulant sidewalls.