Asymmetrical Dielectric-Metal Adhesion for Low-Loss Electronic Packages
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Solution Overview
Problem
Conventional adhesion techniques for high-speed data transfer in integrated circuit devices are inadequate, leading to increased insertion loss and high costs due to the need for expensive materials like SiNx, which are not cost-effective for widespread use in Si wafer-based device fabrication.
Innovation Solution
An asymmetrical package substrate is developed with a smooth adhesion layer on one side and roughened conductive features on the other, using a one-sided dry SiNx deposition process and wet etching to reduce the need for extensive adhesion layer deposition, allowing for better adhesion without compromising signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesion techniques are used for high-speed data transfer, then adhesion between conductors and dielectric layers is achieved, but insertion loss increases and costs increase due to expensive materials like SiNx
Solution Approach 1:
The patent applies different surface treatments to different locations of the conductor: the top surface (signal-facing side) remains smooth to minimize insertion loss for high-speed signals, while the bottom surface (adhesion-facing side) is roughened to enhance adhesion to the dielectric layer. This local differentiation resolves the contradiction between adhesion strength and signal quality.
Solution Approach 2:
The conductor structure is made asymmetrical with respect to surface roughness: one side is smooth and the other side is rough. This asymmetrical design allows the smooth side to maintain low insertion loss while the rough side provides strong adhesion, thereby resolving the technical contradiction.
2Reliability
If expensive adhesion materials like SiNx are used, then adhesion is improved, but manufacturing cost increases making it not cost-effective for widespread use
Solution Approach 1:
The patent changes the surface roughness parameter of the conductor bottom surface to enhance adhesion. By controlling the roughness parameter (e.g., Ra value) through etching processes, strong adhesion is achieved without requiring expensive SiNx materials, thereby reducing manufacturing costs while maintaining reliability.
3Reliability
If conductor surfaces are roughened to improve adhesion, then adhesion strength increases, but signal quality deteriorates due to increased insertion loss
Solution Approach 1:
The patent applies selective surface treatment where only the bottom surface of the conductor is roughened for adhesion, while the top surface remains smooth to preserve signal quality. This localized approach ensures that signal transmission is not degraded while adhesion is enhanced.
Solution Approach 2:
The conductor surface is segmented into two distinct zones: a smooth signal-facing surface and a rough adhesion-facing surface. This segmentation allows each surface to be optimized for its specific function, resolving the contradiction between adhesion and signal quality.
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 provides strong adhesion for smooth conductors, reduces insertion loss, and lowers costs by minimizing the use of expensive adhesion materials, while maintaining the integrity of high-speed signal transmission.
Implementation Method 1
a first adhesion layer is formed over the conductive feature using a one-sided physical vapor deposition process
Implementation Method 2
The conductive feature on the second side is roughened
Data Source
AI summary
An electronic device package comprises a substrate with a first side and a second side opposite the first side; a first conductive feature on the first side and having a first surface; a first dielectric material in contact with the first surface, wherein the first dielectric material has a first composition comprising silicon and nitrogen; a second conductive feature on the second side of the substrate and having a second surface; and a second dielectric material in contact with the second surface, wherein the second dielectric material has a second composition different than the first composition, and wherein a surface roughness of the second surface is greater than a surface roughness of the first surface.