SiNx Adhesion Holes for Low-Loss Package Substrates
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Solution Overview
Problem
In electronic packaging, smooth copper traces are difficult to adhere to overlying layers, leading to reduced robustness of the package substrate, while roughening copper surfaces to improve adhesion increases insertion loss, making it challenging to meet targets for high-speed input/output interconnect architectures.
Innovation Solution
The use of a SiNx adhesion promoting layer with adhesion holes allows for improved adhesion between layers without blocking outgassing and simplifies electrical connections, maintaining smooth copper surfaces for better insertion loss characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If copper surfaces are roughened to improve adhesion between layers, then adhesion strength is improved, but insertion loss increases
Solution Approach 1:
The copper trace surface is segmented into roughened regions (for adhesion) and smooth regions (for low insertion loss). The smooth regions are maintained in areas where signal transmission occurs, while roughened regions are created only where adhesion is critical, such as at the interfaces with overlying layers. This segmentation allows simultaneous optimization of both adhesion strength and insertion loss characteristics.
Solution Approach 2:
Different surface qualities are applied to different locations on the copper traces. The copper surface transitions from a uniform roughened state to a localized state where smooth regions exist along the trace pathways for low insertion loss, while roughened regions are concentrated at specific locations for enhanced adhesion. This local differentiation resolves the contradiction by applying the appropriate surface quality only where needed.
2Loss of energy
If smooth copper traces are used to reduce insertion loss, then insertion loss is reduced, but adhesion to overlying layers deteriorates
Solution Approach 1:
The copper trace surface is segmented into roughened regions (for adhesion) and smooth regions (for low insertion loss). The smooth regions are maintained in areas where signal transmission occurs, while roughened regions are created only where adhesion is critical, such as at the interfaces with overlying layers. This segmentation allows simultaneous optimization of both adhesion strength and insertion loss characteristics.
Solution Approach 2:
Different surface qualities are applied to different locations on the copper traces. The copper surface transitions from a uniform roughened state to a localized state where smooth regions exist along the trace pathways for low insertion loss, while roughened regions are concentrated at specific locations for enhanced adhesion. This local differentiation resolves the contradiction by applying the appropriate surface quality only where needed.
3Strength
If adhesion promoting liner is deposited over entire dielectric buildup layer to accommodate smooth copper traces, then adhesion is improved, but outgassing capability is blocked and manufacturing complexity increases
Solution Approach 1:
The adhesion promoting liner is extracted from being a continuous blanket layer and is instead applied only to specific regions where adhesion is required. By removing the liner from areas where it is not needed (such as over the entire dielectric buildup layer), the patent eliminates the blocking of outgassing pathways and reduces the complexity of subsequent removal processes, while still maintaining adhesion where smooth copper traces are present.
Solution Approach 2:
The adhesion promoting liner is applied selectively to specific locations rather than uniformly across the entire substrate. This localized application ensures that the liner is present only where smooth copper traces require adhesion enhancement, while leaving other areas free for outgassing and reducing overall manufacturing complexity. The liner's presence is differentiated by location and function.
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 enhances the robustness of the package substrate by ensuring good adhesion and reducing manufacturing complexity, while maintaining low insertion losses compatible with high-speed interconnect architectures.
Implementation Method 1
The adhesion promoting liner is deposited with a blanket deposition process
Implementation Method 2
the adhesion promoting layer blocks the ability to outgas the underlying buildup layer
Data Source
AI summary
Embodiments disclosed herein include electronic packages. In an embodiment, the electronic package comprises a first layer, where the first layer is a dielectric material, and a trace on the first layer. In an embodiment, a pad is on the first layer, and a liner is over the first layer, the trace, and the pad, where a hole is provided through the liner. In an embodiment, the electronic package further comprises a second layer over the first layer, the trace, the pad, and the liner.