Copper Wire Barrier Layer Adhesion and Thermal Stability
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Solution Overview
Problem
Copper wires in semiconductor devices face issues with adhesion to insulating films and diffusion due to poor properties, requiring a conductive barrier layer, which complicates the fabrication process and is unstable under heat.
Innovation Solution
A copper wire with a barrier layer formed from copper oxide (Cu2O or CuOxNy) is fabricated within the same chamber as the copper conductive layer, using reactive sputtering with specific gas combinations to enhance adhesion and thermal stability without additional fabrication steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a barrier layer of Cu3N is formed to improve adhesion and prevent copper diffusion, then adhesion to insulating films is improved, but the barrier layer becomes unstable under heat and reduces to Cu causing loss of barrier function
Solution Approach 1:
The patent changes the chemical composition parameters of the barrier layer from Cu3N (copper nitride) to Cu2O (copper oxide) or CuOxNy (copper oxynitride). This parameter change maintains the barrier function and adhesion properties while significantly improving thermal stability, preventing reduction to Cu under heat treatment conditions.
Solution Approach 2:
The patent employs composite material structures where the barrier layer is formed as a combination of copper oxide and copper oxynitride phases (Cu2O and CuOxNy). This composite approach leverages the complementary properties of both materials to achieve both adhesion and thermal stability simultaneously.
2Reliability
If a barrier layer of Ti, TiN, or TaN is formed to improve adhesion and prevent copper diffusion, then adhesion is improved, but the fabrication process becomes complicated requiring separate chambers
Solution Approach 1:
The patent merges the barrier layer formation process with the copper conductive layer deposition process by using the same sputtering chamber for both operations. The barrier layer is formed first, then the copper layer is deposited in the same chamber without requiring separate fabrication equipment, thereby simplifying the overall device structure and fabrication process.
Solution Approach 2:
The sputtering chamber is designed to perform multiple functions: forming both the barrier layer and the copper conductive layer. This multi-functionality eliminates the need for separate fabrication chambers and processes, reducing device complexity while maintaining the necessary barrier properties.
3Area of stationary object
If wire area is reduced to occupy less area and enable fast processing, then area occupancy is reduced, but resistance increases causing signal delay
Solution Approach 1:
The patent changes the material parameter from aluminum to copper for the conductive layer. Copper has superior electrical conductivity (approximately 5-6 times higher than aluminum), which compensates for the reduced wire area by lowering resistance, thereby maintaining signal transmission quality despite smaller dimensions.
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 simplifies the fabrication process, maintains barrier layer stability under heat, and improves adhesion to insulating films, preventing copper diffusion and signal delay.
Implementation Method 1
forming a Cu2O layer on the substrate by using O2 gas; removing the O2 gas, and forming a copper layer on the Cu2O layer within the same chamber
Implementation Method 2
forming a barrier layer and a copper conductive layer within the same chamber having a copper target provided therein by changing a type of gas applied at a time
Data Source
AI summary
The present invention relates to a copper wire in a semiconductor device in which a barrier layer is formed for improving adhesion of a copper wire without any additional fabricating step; a method for fabricating the same, and a flat panel display device with the same. The copper wire includes a barrier layer formed on an underlying structure, and a copper conductive layer on the barrier layer, wherein the barrier layer includes at least one of a Cu2O layer and a CuOxNy layer.