Organic Adhesion Promoter Layer for Low-Loss Copper Dielectric Bonding

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Solution Overview

Problem

Current package assembly technologies face challenges in maintaining mechanical stability and reducing insertion loss at high frequencies due to weak bonding between copper surfaces and dielectrics, often resulting in delamination and increased manufacturing costs.

Innovation Solution

The use of a semi-additive process with an organic adhesion promoter (OAP) film to create a smooth interface between copper traces and vias, reducing electrical resistance and preventing delamination, while maintaining a cost-effective manufacturing process by avoiding wet desmear chemicals and using a sputtered seed process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a roughened copper surface is used to promote dielectric adhesion, then mechanical stability is improved, but electrical resistance increases and insertion loss worsens at high frequencies

Engineering Contradiction:

Improvemechanical stabilityVSAvoidinsertion loss

Core Design Contradiction:

Stability of the object's compositionVSLoss of energy

Solution Approach 1:

An organic adhesion promoter (OAP) layer is introduced as an intermediary substance between the copper trace surface and the dielectric layer. This OAP layer provides both mechanical anchoring for the dielectric (through its adhesive properties) and maintains electrical conductivity (through its conductive formulation), thereby resolving the contradiction between mechanical stability and electrical performance without requiring surface roughening

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the chemical and physical parameters of the copper-dielectric interface by applying a conductive OAP coating. Instead of modifying the copper surface topology (roughening), the solution modifies the chemical composition and surface properties of the interface layer, transforming it from a purely mechanical adhesion solution to a dual-function layer that provides both mechanical bonding and electrical conductivity

Inventive Principle:

Principle #35Parameter changes

2Strength

If wet desmear chemicals are used in the manufacturing process, then dielectric adhesion is improved, but manufacturing cost and process complexity increase

Engineering Contradiction:

Improvedielectric adhesionVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The invention replaces the chemical-mechanical wet desmear process with a sputtering-based physical vapor deposition process. Instead of using wet chemicals to prepare the surface for adhesion, a sputtered seed layer is deposited to create a conductive surface that works synergistically with the OAP formulation, eliminating the need for wet desmear chemicals and associated cleaning infrastructure

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The manufacturing process parameters are changed from wet chemical treatment (desmear) to physical vapor deposition (sputtering). This parameter change transforms the surface preparation method from a chemical etching and cleaning process to a controlled deposition process, simplifying the manufacturing flow and reducing chemical handling requirements while maintaining or improving adhesion performance

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If a smooth copper interface is used to reduce electrical resistance, then insertion loss is reduced, but dielectric adhesion deteriorates

Engineering Contradiction:

Improveelectrical resistanceVSAvoiddielectric adhesion

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The interface structure is transformed from a simple copper-dielectric bimaterial interface to a tri-layer composite structure consisting of copper trace, organic adhesion promoter layer, and dielectric layer. This composite structure allows the copper-OAP interface to remain smooth (maintaining low electrical resistance) while the OAP-dielectric interface provides strong mechanical adhesion, thereby resolving the contradiction between electrical and mechanical performance

Inventive Principle:

Principle #40Composite 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 enhances the mechanical stability of package assemblies, reduces insertion loss, and enables high-frequency operation while maintaining a cost-effective manufacturing flow, improving overall reliability and performance.

Implementation Method 1

using a sputtered seed process

Methodology Applied

Scientific EffectSputtering: Sputtering

Data Source

PatentUS20230420322A1Organic adhesion promotor for dielectric adhesion to a copper trace

Publication Date: 2023.12.28 INTEL CORP

AI summary

Embodiments herein relate to systems, apparatuses, or processes directed to an organic adhesion promoter layer on the surface of a copper trace to reduce delamination between a dielectric material and the surface of the copper trace, and to facilitate a smooth surface interface between the surface of the copper trace and of a copper feature, such as a copper-filled via, placed on the surface of the copper trace. The smooth surface interface reduces insertion loss and enables routing of higher frequency signals on a package, and does not require roughing of the copper trace in order to adhere to the dielectric material. Other embodiments may be described and/or claimed.