Nitrided Package Metallization for Low-Loss High-Density Routing
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Solution Overview
Problem
Next-generation multi-chip packaging requires higher interconnect density and lower signal loss at higher frequencies, which existing semi-additive techniques struggle to achieve due to limitations in trace density and roughness, especially at frequencies exceeding 28 GHz where signal sensitivity increases.
Innovation Solution
The implementation of nitrided metallization features with a metal nitride surface layer, which enhances adhesion with organic dielectric materials, reducing surface roughness and insertion losses, and allowing for smoother signal transmission through chemical treatment rather than mechanical roughening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional semi-additive techniques are used for metallization, then manufacturing simplicity is maintained, but interconnect trace density and surface smoothness deteriorate at high frequencies
Solution Approach 1:
The patent applies parameter changes by modifying the metallization surface chemistry through nitridation treatment. This chemical treatment alters the surface properties of the copper metallization, reducing surface roughness and improving adhesion without requiring complete process reconfiguration. The nitridation process changes the surface composition and morphology parameters to achieve smoother traces suitable for high-frequency signals.
Solution Approach 2:
The patent replaces mechanical roughening methods with chemical nitridation treatment. Instead of using mechanical means to prepare the surface, the invention employs chemical reactions (nitridation) to achieve the desired surface smoothness and adhesion properties, thereby reducing mechanical complexity while improving surface quality.
2Productivity
If interconnect trace density is increased to support next-generation packaging, then bandwidth and speed are improved, but signal loss and surface roughness effects worsen
Solution Approach 1:
The nitridation treatment modifies surface parameters (composition, roughness, adhesion) to enable higher trace density while maintaining signal integrity. By changing the surface chemistry, the patent reduces skin effect losses and enables closer trace spacing without proportionally increasing signal loss.
Solution Approach 2:
The patent converts the potential harm of increased trace density (which typically increases mutual coupling and signal loss) into a benefit by using nitridation to create smoother surfaces with better controlled impedance. The chemical treatment transforms what would be a harmful high-density configuration into a beneficial low-loss interconnect structure.
3Strength
If mechanical roughening is used to enhance adhesion, then bonding strength is improved, but surface smoothness and signal transmission quality deteriorate
Solution Approach 1:
The patent replaces mechanical roughening with chemical nitridation to achieve adhesion enhancement. The nitridation process creates strong chemical bonds at the metallization-dielectric interface without the mechanical surface disruption that would degrade signal transmission. This substitution simultaneously achieves both strong adhesion and surface smoothness.
Solution Approach 2:
The invention changes the adhesion mechanism from mechanical interlocking (through roughening) to chemical bonding (through nitridation). This parameter change in the adhesion mechanism allows the surface to remain smooth while still achieving strong bonding between the metallization and organic dielectric materials.
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 enables higher frequency data signal transmission with reduced insertion losses and improved adhesion, supporting higher interconnect densities and frequencies without significant dimensional loss, suitable for 2D, 2.5D, and 3D multi-chip packages.
Implementation Method 1
one or more surfaces of metallization features within an IC device package are nitrided to improve the adhesion of one or more organic dielectric build-up materials applied over the metallization features
Data Source
AI summary
High-density IC die package routing structures with one or more nitrided surfaces. Metallization features may be formed, for example with a plating process. Following the plating process, a surface of the metallization features may be exposed to a surface treatment that incorporates nitrogen onto a surface of the metallization. The presence of nitrogen may chemically improve adhesion between finely patterned metallization features and package dielectric material. Accordingly, surface roughness of metallization features may be reduced without suffering delamination. With lower surface roughness, metallization features may transmit higher frequency data signals with lower insertion loss.