SiNx Surface Finish for Smooth Copper I/O Package Interfaces
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Solution Overview
Problem
The increasing off-package I/O bandwidth and data rates in microelectronics packages are hindered by the limitations of electrical I/O reach and energy efficiency, leading to an approaching I/O power wall, as traditional solder resist layers are cumbersome and costly, requiring roughened surfaces and adding Z-height to the packages.
Innovation Solution
The use of silicon nitride (SiNx) films as a surface finish eliminates the need for solder resist layers, providing a smooth copper interface for high-speed input/output and reducing manufacturing costs by eliminating the roughening process, while allowing for thinner packages with more compact designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional solder resist layers are used to protect copper surfaces, then protection is provided, but the surface must be roughened and Z-height increases
Solution Approach 1:
The patent changes the material parameter from organic solder resist to inorganic SiNx film, which fundamentally alters the protection mechanism. SiNx provides protection through chemical inertness and adhesion to smooth surfaces, eliminating the need for roughening while maintaining thin profile
Solution Approach 2:
The SiNx film serves as a thin, disposable protective layer that can be applied directly without complex preparation. The film thickness is kept minimal (e.g., 50-200 nm) while providing sufficient protection, replacing the thicker solder resist approach
2Reliability
If solder resist layers are used to protect copper surfaces, then protection is provided, but manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the roughening process step from the manufacturing sequence. By applying SiNx directly to smooth copper surfaces, the complex multi-step solder resist application process is replaced with a single deposition step, reducing both cost and complexity
Solution Approach 2:
The patent replaces the mechanical roughening process with a chemical vapor deposition process for SiNx film formation. This substitution eliminates the need for mechanical surface preparation while achieving superior protection with simpler manufacturing
3Reliability
If copper surfaces are roughened for solder resist adhesion, then adhesion is improved, but surface smoothness for high-speed signals is lost
Solution Approach 1:
The patent changes the adhesion mechanism parameter from mechanical interlocking (requiring rough surfaces) to chemical bonding (working with smooth surfaces). SiNx forms strong chemical bonds with copper at atomic level, enabling adhesion without surface roughening and preserving signal integrity
Solution Approach 2:
The patent creates a composite interface between SiNx film and smooth copper surface. This composite structure combines the protective properties of SiNx with the electrical properties of smooth copper, achieving both adhesion and signal performance simultaneously
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
SiNx films enable enhanced electrical performance and reduced manufacturing costs by providing a protective layer for copper surfaces without the need for roughened surfaces, resulting in more efficient and compact microelectronics packages with improved computing power.
Implementation Method 1
a layer including silicon and nitrogen is formed on the core material
Implementation Method 2
a layer including silicon and nitrogen is formed on the core material
Data Source
AI summary
Disclosed herein are microelectronics package architectures utilizing SiNx based surface finishes and methods of manufacturing the same. The microelectronics packages may include a core material, a first plurality of pads, and a silicon nitride layer. The first plurality of pads are attached to the core material. The silicon nitride layer is attached to the core material. The silicon nitride material defines respective openings to expose at least a portion of each of the first plurality of pads.