Semiconductor Package Stiffener Structure for Warpage Control
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Solution Overview
Problem
Conventional semiconductor packages face issues such as excess cost, decreased reliability, and large package sizes due to problems like warpage, package distortion, bending, component cracking, and delamination, which are not adequately addressed by existing technologies.
Innovation Solution
The introduction of a stiffener at the peripheral edge of a substrate with electronic components, encapsulated by an encapsulant, which covers the lateral sides and top side of the stiffener, reducing thermal stress and improving attachment integrity, thereby enhancing package reliability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional semiconductor packages are manufactured without additional stiffening structures, then manufacturing process is simpler, but warpage and package distortion occur due to thermal stress
Solution Approach 1:
A stiffener structure is attached to the substrate before the encapsulant molding process. This preliminary action provides thermal stress compensation and structural support during subsequent packaging and operation, preventing warpage and delamination before they occur.
Solution Approach 2:
The stiffener is constructed from composite materials with specific mechanical properties that differ from both the substrate and encapsulant. This composite structure creates a thermal stress compensation mechanism that balances the coefficient of thermal expansion differences, reducing warpage while maintaining structural integrity.
2Shape
If a stiffener structure is added to reduce warpage, then package flatness and reliability improve, but manufacturing complexity increases
Solution Approach 1:
The stiffener is designed as a separate, modular component that can be independently manufactured and then attached to the substrate. This segmentation allows for specialized stiffener production using optimized processes, and simplifies assembly by enabling attachment before encapsulant molding, avoiding complex post-processing steps.
3Manufacturing precision
If stiffener lateral sides are exposed from encapsulant, then stiffener thickness can be controlled, but attachment integrity between encapsulant and substrate deteriorates
Solution Approach 1:
The stiffener is completely embedded within the encapsulant material, with the encapsulant surrounding the stiffener's lateral sides. This nesting configuration provides full surface area contact between the encapsulant and stiffener, maximizing attachment integrity while allowing precise thickness control of the stiffener through selective removal processes.
4Manufacturing precision
If stiffener material is selectively removable, then thickness can be adjusted, but additional manufacturing steps are required
Solution Approach 1:
The stiffener is manufactured with a thickness greater than the final desired thickness. After encapsulant molding, the excess stiffener material is selectively removed through grinding or other precision removal processes. This parameter change approach enables precise thickness control while using a straightforward, scalable manufacturing sequence that maintains high productivity.
Data Source
AI summary
In one example, an electronic device includes a substrate including a first side with a peripheral portion and a central portion, a second side, a lateral side, a dielectric structure, and a conductive structure. An electronic component includes a component first side coupled to the conductive structure in the central portion, a component second side, and a component lateral side. A stiffener is coupled to the first side in the peripheral portion and includes an inner wall, an outer wall opposite to the inner wall, and a top side. An encapsulant covers the inner wall, the outer wall, and the component lateral side, and a portion of the first side. The component second side can be exposed from the top side of the encapsulant. Other examples and related methods are also disclosed herein.