UBM Sloped Sidewalls for Semiconductor Package Adhesion
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing the size of electronic components and packaging, requiring smaller packages that minimize area usage while ensuring reliability and preventing delamination issues in wafer-level packaging.
Innovation Solution
The implementation of a package structure with a redistribution structure and under ball metallizations (UBMs) featuring sloped sidewalls and an adhesion layer, which enhances adhesion and reduces delamination by increasing surface area for the dielectric layer, thereby improving package reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the package size is reduced to minimize area usage, then the area efficiency is improved, but the adhesion strength deteriorates leading to delamination issues
Solution Approach 1:
The patent transitions from a two-dimensional planar UBM interface to a three-dimensional structure with vertical sidewalls. The UBM features substantially vertical sidewalls extending upward from the package substrate, creating additional surface area for adhesion without increasing the horizontal package footprint. This dimensional change allows maintaining adhesion strength while reducing package area.
Solution Approach 2:
The patent modifies the geometric parameters of the UBM structure by changing from flat horizontal surfaces to vertical sidewalls with specific height and orientation. This parameter change increases the effective adhesion surface area and improves mechanical interlocking with the dielectric layer, thereby enhancing adhesion strength without expanding the package area.
2Area of moving object
If the package size is reduced to minimize area usage, then the area efficiency is improved, but the reliability deteriorates due to delamination
Solution Approach 1:
By extending the UBM vertically with substantially vertical sidewalls, the patent creates additional adhesion interfaces in the vertical dimension. This increases the total bonding surface area between the UBM and dielectric layer, improving package reliability through enhanced mechanical interlocking without increasing the horizontal package footprint.
Solution Approach 2:
The patent employs a composite structure consisting of the UBM metal layer combined with the dielectric layer in a vertically integrated configuration. The combination of vertical UBM sidewalls and dielectric material creates a composite adhesion system that enhances reliability through multiple interaction mechanisms including mechanical interlocking and adhesive bonding.
3Strength
If the UBM has vertical sidewalls to increase adhesion surface area, then the adhesion strength is improved, but the manufacturing complexity increases
Solution Approach 1:
The substantially vertical sidewalls of the UBM serve multiple functions simultaneously: they increase adhesion surface area, provide mechanical interlocking with the dielectric layer, and define the lateral boundaries of the UBM structure. This multi-functionality reduces the need for additional separate structural elements, thereby limiting the increase in manufacturing complexity while achieving improved adhesion strength.
4Productivity
If smaller packages are used to integrate more components, then the integration density is improved, but the delamination resistance deteriorates
Solution Approach 1:
The patent uses vertical extension of UBM sidewalls to increase adhesion surface area within the vertical dimension, allowing smaller horizontal package footprints to maintain adequate delamination resistance. This enables higher integration density by accommodating more components in reduced area while the vertical UBM structure compensates for the reduced horizontal adhesion area.
Solution Approach 2:
By changing the geometric parameters of the UBM to include vertical sidewalls with specific heights and orientations, the patent increases the effective adhesion area per unit horizontal footprint. This parameter change allows smaller packages to achieve the same delamination resistance as larger packages, thereby enabling higher integration density.
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
This approach allows for more efficient use of space and enhances the reliability of semiconductor packages by reducing delamination and improving uniformity of the dielectric layer, addressing the need for smaller, more integrated electronic components.
Implementation Method 1
an adhesion layer, which enhances adhesion and reduces delamination by increasing surface area for the dielectric layer
Data Source
AI summary
Package structures and methods of forming package structures are discussed. A package structure, in accordance with some embodiments, includes an integrated circuit die, an encapsulant at least laterally encapsulating the integrated circuit die, a redistribution structure on the integrated circuit die and the encapsulant, a connector support metallization coupled to the redistribution structure, and an external connector on the connector support metallization. The redistribution structure includes a dielectric layer disposed distally from the encapsulant and the integrated circuit die. The connector support metallization has a first portion on a surface of the dielectric layer and has a second portion extending in an opening through the dielectric layer. The first portion of the connector support metallization has a sloped sidewall extending in a direction away from the surface of the dielectric layer.