Molecular Self-Assembly for Copper Interconnect Diffusion Barriers
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Solution Overview
Problem
Current methods for forming copper interconnections in electronic devices face challenges such as poor adhesion and diffusion of copper into dielectric materials, especially with porous dielectrics, due to limitations in existing barrier layer deposition techniques like PVD and ALD, which affect the conductivity and reliability of interconnects.
Innovation Solution
The use of molecular self-assembly to form a molecularly self-assembled layer (MSAL) between dielectric and conductive materials, which acts as a diffusion barrier and adhesion layer, sealing pores in porous dielectrics and providing improved adhesion properties, thereby eliminating the need for conventional barrier layers and enhancing the reliability of copper interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional barrier layer deposition techniques (PVD or ALD) are used, then copper can be deposited to form interconnections, but copper diffusion into dielectric materials occurs and adhesion is poor
Solution Approach 1:
A molecularly self-assembled layer (MSAL) is formed on the dielectric material surface before copper deposition. This preliminary MSAL layer seals pores in porous dielectrics and provides a surface that prevents copper diffusion while promoting good adhesion, eliminating the need for conventional barrier layers.
Solution Approach 2:
The MSAL acts as an intermediary layer between the dielectric material and copper. It mediates the interaction by providing a surface that simultaneously prevents copper diffusion into the dielectric and promotes copper adhesion, resolving the contradiction between diffusion prevention and adhesion.
2Reliability
If porous dielectric materials are used to reduce capacitance, then signal integrity improves, but copper diffusion into the porous structure increases
Solution Approach 1:
The MSAL layer provides localized pore sealing at the dielectric-copper interface while maintaining the bulk porous structure of the dielectric material. This local modification prevents copper diffusion into pores without compromising the overall low-k properties and signal integrity benefits of the porous dielectric.
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 MSAL effectively prevents copper diffusion into dielectric materials, improves adhesion, and ensures reliable copper interconnects with improved conductivity and reduced electron scattering, even in porous low-k dielectrics, thereby addressing the limitations of existing barrier layer deposition techniques.
Implementation Method 1
Molecular self-assembly has been used to produce very small structures and features, e.g., structures and features having a characteristic dimension at or below the nanometer size scales.
Implementation Method 2
The barrier layer should also adhere well to the dielectric material and to the copper subsequently formed on the barrier layer.
Data Source
AI summary
Systems and methods for molecular self-assembly are provided. The molecular self-assembly receives a substrate that includes one or more regions of dielectric material. A molecularly self-assembled layer is formed on an exposed surface of the dielectric material. The molecularly self-assembled layer includes material(s) having a molecular characteristic and/or a molecular type that includes one or more of a molecular characteristic and/or a molecular type of a head group of molecules of the material, a molecular characteristic and/or a molecular type of a terminal group of molecules of the material, and a molecular characteristic and/or a molecular type of a linking group of molecules of the material. The molecular characteristic(s) and molecular type(s) are selected according to at least one pre-specified property of the molecularly self-assembled layer.