Intermetallic Compound Wiring Structure for Semiconductor Devices
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Solution Overview
Problem
The miniaturization of semiconductor device components leads to increased electrical resistivity in multilayer wiring structures due to copper's mean free path limitations, and the use of alternative metals often results in surface aggregation and the need for diffusion barrier layers, which further increase resistivity.
Innovation Solution
A wiring structure utilizing an intermetallic compound as the conductor, specifically containing metal elements like Al, Fe, Co, Ni, and Zn, which eliminates the need for a diffusion barrier layer by forming a strong bond with the insulator, maintaining low resistivity even at narrow line widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as the conductor material in miniaturized wiring structures, then excellent conductivity is achieved at larger dimensions, but electrical resistivity excessively increases when line width or line height is 40 nm or less due to mean free path limitations
Solution Approach 1:
The patent changes the material parameter from pure copper to an intermetallic compound (such as CoAl, FeAl, NiAl, CuAl2, or NiSb), which fundamentally alters the electrical conduction mechanism. This material substitution allows the wiring to maintain low electrical resistivity even at line widths of 40 nm or less, overcoming the mean free path limitation that plagues copper at such small dimensions.
Solution Approach 2:
The patent employs intermetallic compounds as composite materials that combine the beneficial properties of different metals. These compounds exhibit both excellent electrical conductivity and strong adhesion to insulators, while eliminating the need for diffusion barrier layers. The intermetallic compound structure provides a unique conduction pathway that remains effective at nanoscale dimensions.
2Reliability
If alternative metals (Rh, Ir, Ni, Mo, Co, Ru) are used to replace copper for maintaining conductivity at small dimensions, then electrical resistivity is controlled, but the metals tend to aggregate on the insulator surface and are difficult to embed in wiring grooves
Solution Approach 1:
The patent uses intermetallic compounds that possess both controlled electrical resistivity and improved embeddability. The specific crystal structure and surface properties of these compounds prevent aggregation on insulator surfaces while allowing complete filling of wiring grooves, thus resolving both the conductivity and manufacturing challenges.
Solution Approach 2:
The patent modifies the material parameters by selecting intermetallic compounds with specific compositions and crystal structures that optimize both electrical properties and adhesion characteristics. This parameter optimization enables the material to be easily deposited and embedded in narrow grooves without aggregation, while maintaining low electrical resistivity.
3Productivity
If the multilayer wiring structure is miniaturized to achieve high performance semiconductor devices, then device performance is improved, but the electrical resistance of the conductor wiring increases due to reduced cross-section and mean free path effects
Solution Approach 1:
The patent changes the fundamental material parameter from copper to an intermetallic compound, which alters the electrical conduction characteristics. This material substitution allows the wiring to maintain low electrical resistance even as the wiring dimensions are reduced for device miniaturization, thus enabling high-performance devices without the resistivity penalty.
Solution Approach 2:
The use of intermetallic compounds as composite materials provides a solution that maintains excellent electrical conductivity at reduced dimensions. The unique atomic structure and bonding characteristics of these compounds enable efficient electron transport even in narrow interconnects, supporting continued device miniaturization.
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 allows for high-performance semiconductor devices with reduced effective electrical resistivity and improved adhesion between the conductor and insulator, enabling efficient miniaturization without the need for diffusion barrier layers.
Implementation Method 1
a wiring structure including a conductor containing an intermetallic compound and an insulator layer
Implementation Method 2
the intermetallic compound contains two or more kinds of metal elements selected from the group consisting of Al, Fe, Co, Ni, and Zn
Data Source
AI summary
To provide a wiring material which does not require a diffusion barrier layer and exhibits excellent conductivity and adhesion property between a conductor and an insulator and a semiconductor element using the same. The wiring structure of the present invention includes a conductor containing an intermetallic compound and an insulator layer. The intermetallic compound preferably contains two or more kinds of metal elements selected from the group consisting of Al, Fe, Co, Ni, and Zn. In addition, the intermetallic compound is preferably one or more kinds selected from an intermetallic compound containing Al and Co, an intermetallic compound containing Al and Fe, an intermetallic compound containing Al and Ni, an intermetallic compound containing Co and Fe, or an intermetallic compound containing Ni and Zn.