Semiconductor Seed Layer Protrusion for Adhesion
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Solution Overview
Problem
Existing semiconductor packages face challenges in achieving high integration density and reliable electrical connections due to limitations in adhesion and diffusion of metals, leading to instability in impedance and reliability during testing.
Innovation Solution
The implementation of a redistribution layer structure with a seed layer structure that includes a lining layer and an overlying seed layer, where the edge of the seed layer is protruded and embedded by a polymer layer, enhancing adhesion and preventing metal diffusion to the underlying device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal features are directly formed on the substrate without a protruding seed layer structure, then the manufacturing process is simpler, but the adhesion between metal and polymer material is insufficient and metal diffusion occurs
Solution Approach 1:
A seed layer structure is formed on the substrate before the metal feature is deposited. The seed layer structure includes a lining layer and a seed layer, where the seed layer protrudes from the metal feature. This preliminary formation of the seed layer structure provides a foundation that enhances adhesion between the metal feature and the polymer material, and prevents metal diffusion during subsequent processing steps.
2Reliability
If the seed layer structure is aligned with the metal feature edge, then the structure is simpler to manufacture, but it cannot effectively prevent metal diffusion to the underlying device
Solution Approach 1:
The seed layer structure is designed with an asymmetric configuration where the seed layer protrudes from the metal feature beyond the metal feature's edge. This asymmetric design creates an overlapping region between the seed layer and the polymer material that extends beyond the metal feature boundary, providing an effective barrier against metal diffusion while maintaining manufacturability through standard photolithography and etching processes.
3Reliability
If the metal feature occupies the entire width of the conductor, then the electrical connection is maximized, but the impedance becomes unstable during reliability testing
Solution Approach 1:
The conductor structure is designed with varying metal thickness in different regions. The metal feature has a first width at its edge and a second width at its center, where the first width is less than the second width. This creates a tapered or non-uniform metal distribution that maintains adequate electrical connection while reducing overall metal quantity and stabilizing impedance characteristics during reliability testing.
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 solution stabilizes the impedance and improves the reliability of semiconductor packages by enhancing the interface adhesion between metals and polymer materials, reducing metal diffusion and maintaining package integrity during reliability tests.
Implementation Method 1
enhancing the interface adhesion between metals and polymer materials
Data Source
AI summary
Conductive structures, semiconductor packages and methods of forming the same are disclosed. A semiconductor package includes at least one die and a redistribution layer. The redistribution layer is disposed over and electrically to the at least one die and includes a seed layer structure and a metal feature over the seed layer structure. In some embodiments, an edge of the seed layer structure is protruded from an edge of the metal feature and has a surface roughness Rz greater than 10 nm.