Tungsten Alloy Interconnects Without Copper Barrier Layers
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Solution Overview
Problem
Current integrated circuit (IC) device technologies face challenges in achieving smaller feature sizes and reliable electrical interconnects due to issues with copper migration and the need for barrier layers, which complicate processing and affect performance.
Innovation Solution
The use of cobalt-tungsten and nickel-tungsten alloys as conducting materials for interconnects, liner layers, and capping layers in semiconductor devices, deposited through electroless processes, eliminates the need for barrier layers and enhances copper migration resistance, allowing for more efficient and reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper is used as interconnect material, then electrical conductivity is improved, but copper migration occurs requiring additional barrier layers
Solution Approach 1:
The patent extracts copper from the interconnect structure entirely, replacing it with cobalt-tungsten or nickel-tungsten alloys. This eliminates the source of copper migration problems while maintaining electrical conductivity, thereby removing the need for barrier layers and simplifying the overall device structure.
Solution Approach 2:
The patent changes the material composition parameters by introducing tungsten (15-45 atomic percent) combined with cobalt or nickel. This compositional change provides both copper migration resistance and electrical conductivity without requiring additional barrier layers, thus resolving the contradiction between reliability and processing complexity.
2Reliability
If barrier layers are added to prevent copper migration, then copper diffusion is blocked, but processing steps increase
Solution Approach 1:
The patent removes the need for separate barrier layers by extracting the barrier function and integrating it into the interconnect material itself through the use of cobalt-tungsten or nickel-tungsten alloys, which inherently resist copper diffusion while maintaining conductivity.
Solution Approach 2:
The patent merges the interconnect function and barrier function into a single material system. The cobalt-tungsten or nickel-tungsten alloy simultaneously provides electrical conductivity and copper migration resistance, eliminating the need for separate barrier layers and reducing processing steps.
3Productivity
If feature sizes are reduced, then device density is improved, but material performance demands increase
Solution Approach 1:
The patent changes the material composition parameters by using cobalt-tungsten or nickel-tungsten alloys with specific tungsten content (15-45 atomic percent). This compositional optimization maintains electrical conductivity and copper migration resistance even at reduced feature sizes, enabling higher device density without sacrificing material performance.
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 cobalt-tungsten and nickel-tungsten alloys improve the performance of IC devices by preventing copper diffusion, simplifying processing, and reducing resistance, thereby enabling smaller feature sizes and more reliable electrical interconnects.
Implementation Method 1
deposited through electroless processes
Data Source
AI summary
Conducting alloys comprising cobalt, tungsten, and boron and conducting alloys comprising nickel, tungsten, and boron are described. These alloys can, for example, be used to form metal interconnects, can be used as liner layers for traditional copper or copper alloy interconnects, and can act as capping layers. The cobalt-tungsten and nickel-tungsten alloys can be deposited using electroless processes.