Silicon Nitride Adhesion Layers for Smooth Copper Substrates
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Solution Overview
Problem
Existing integrated circuit packaging technologies face challenges in maintaining reliable adhesion between copper-dielectric interfaces while minimizing signal loss at high frequencies due to surface roughness, which is necessary for adhesion but causes increased signal loss, and existing adhesion promotor films either require high temperatures or have porous structures that compromise reliability.
Innovation Solution
Employing a sputtered silicon nitride adhesion promotor film on smooth copper surfaces using plasma vapor deposition (PVD) to enhance adhesion without roughening, combined with a dry desmear process to remove residues and a rinsing process to eliminate fluorine, ensuring high reliability and low signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If surface roughness is increased to improve adhesion between copper and dielectric layers, then adhesion strength is improved, but signal loss increases at high frequencies
Solution Approach 1:
The patent introduces an adhesion promotor layer as an intermediary substance between the copper surface and dielectric layer. This thin film (5-50 nm) provides chemical bonding sites for both the copper and dielectric materials, enabling strong adhesion without requiring surface roughness. The adhesion promotor layer acts as a mediator that chemically bonds to both surfaces, eliminating the need for mechanical interlocking through roughening while maintaining signal integrity.
2Strength
If conventional adhesion promotor films are used to improve adhesion, then adhesion is enhanced, but manufacturing complexity increases due to high temperature requirements or porous structures
Solution Approach 1:
The patent changes the deposition parameters by using plasma-enhanced chemical vapor deposition (PECVD) at reduced temperatures (200-400°C) compared to conventional methods. This parameter change enables the formation of dense, non-porous adhesion promotor layers with controlled stoichiometry. The plasma activation allows for lower temperature processing while maintaining film density and adhesion properties, thereby simplifying the manufacturing process and reducing thermal constraints on substrate 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
The solution provides reliable adhesion between copper and dielectric layers without increasing signal loss, maintaining package integrity and reducing manufacturing costs by using lower processing temperatures and improving hermeticity, thus enhancing the performance of high-speed packaging systems.
Implementation Method 1
Employing a sputtered silicon nitride adhesion promotor film on smooth copper surfaces using plasma vapor deposition (PVD)
Implementation Method 2
using plasma vapor deposition (PVD) to enhance adhesion
Data Source
AI summary
Substrate assemblies having adhesion promotor layers and related methods are disclosed. An example apparatus includes a substrate, a dielectric layer, a first copper layer between the substrate and the dielectric layer, and a film between the dielectric layer and the first copper layer. The film including silicon and nitrogen and being substantially free of hydrogen. A via in the dielectric layer is to provide access to the first copper layer. A portion of the first copper layer uncovered in the via, a wall of the via and the portion of the first copper layer to be substantially free of fluorine. A seed copper layer positioned on the dielectric layer. The via wall and the portion of the first copper layer. The seed copper layer and the first copper layer define an undercut at an interface between the seed copper layer and the first copper layer.