Passivation and Planarization Layer Anchoring Against Delamination
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Solution Overview
Problem
The existing semiconductor package formation processes face challenges with delamination between the polymer planarization layer and the passivation layer, which affects the reliability and integrity of the interconnect structures.
Innovation Solution
A method is introduced where a polymer planarization layer is formed to extend into the openings of the passivation layer, creating a non-planar interface that reduces delamination by acting as an anchor, and a redistribution line is connected through an Under-Bump-Metallurgy (UBM) to ensure electrical connectivity and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a planarization layer is formed over the passivation layer, then the surface flatness is improved, but delamination occurs between the layers
Solution Approach 1:
The planarization layer is extended vertically into the passivation layer openings, transforming from a purely horizontal overlay to a three-dimensional structure with vertical anchoring components. This dimensional change creates mechanical interlocking that prevents delamination while maintaining surface flatness.
Solution Approach 2:
The planarization layer is nested within the passivation layer structure by extending into its openings, creating a nested configuration where the planarization layer is partially contained within the passivation layer's vertical profile, enhancing adhesion through intimate contact.
2Reliability
If the planarization layer extends into the passivation layer openings, then delamination is reduced, but the manufacturing complexity increases
Solution Approach 1:
The planarization layer is formed to extend into the passivation layer openings during the same formation process, rather than requiring a separate subsequent step. This preliminary action integrates the adhesion-enhancing feature into the base manufacturing flow, reducing overall process complexity.
Solution Approach 2:
The planarization layer serves multiple functions simultaneously: it provides surface flatness for subsequent processing and extends into the passivation layer openings to prevent delamination. This multi-functionality reduces the need for additional specialized structures or processes.
3Reliability
If a UBM is formed to connect the redistribution line, then electrical connectivity is improved, but the process steps increase
Solution Approach 1:
The UBM formation process is merged with the existing planarization and passivation layer formation processes, combining multiple functions (electrical connection, mechanical anchoring, and surface planarization) into an integrated structure that reduces the number of discrete process steps.
Data Source
AI summary
A method includes forming a patterned mask comprising a first opening, plating a conductive feature in the first opening, depositing a passivation layer on a sidewall and a top surface of the conductive feature, and patterning the passivation layer to form a second opening in the passivation layer. The passivation layer has sidewalls facing the second opening. A planarization layer is dispensed on the passivation layer. The planarization layer is patterned to form a third opening. After the planarization layer is patterned, a portion of the planarization layer is located in the second opening and covers the sidewalls of the passivation layer. An Under-Bump Metallurgy (UBM) is formed to extend into the third opening.