Copper Interconnect Adhesion for Group III-V Semiconductor Devices
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Solution Overview
Problem
Conventional group III-V semiconductor devices, such as gallium arsenide (GaAs) devices, face increased resistance and thermal conductivity issues due to the use of gold metal lines, which affect electrical properties and reliability as device size decreases.
Innovation Solution
A copper interconnect with a stacked-layer structure of adhesion layers and a diffusion barrier layer is used to connect group III-V semiconductor devices, preventing copper diffusion and reducing resistance, comprising a first adhesion layer, a diffusion barrier layer, and a second adhesion layer with a copper wire line, fabricated using techniques like sputtering and evaporation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold is used as the metal line material in conventional group III-V semiconductor devices, then the device can be fabricated with traditional processes, but the resistance of the metal line increases and thermal conductivity decreases as line width reduces
Solution Approach 1:
The patent changes the material parameter from gold to copper, which fundamentally alters the electrical and thermal properties. Copper provides lower resistance and higher thermal conductivity, directly resolving the energy loss issue while maintaining compatibility with group III-V semiconductor fabrication processes.
Solution Approach 2:
The patent employs a composite multi-layer structure consisting of adhesion layers (titanium or chromium), diffusion barrier layers (tantalum, tungsten, or titanium nitride), and copper interconnect layers. This composite structure combines the advantages of each material to achieve low resistance, high thermal conductivity, and prevention of copper diffusion into the semiconductor device.
2Ease of manufacture
If gold is used as the metal line material, then the fabrication process is conventional and simple, but the thermal conductive property of the high speed semiconductor device is affected
Solution Approach 1:
The patent changes the material parameter from gold to copper, which fundamentally alters the electrical and thermal properties. Copper provides lower resistance and higher thermal conductivity, directly resolving the energy loss issue while maintaining compatibility with group III-V semiconductor fabrication processes.
3Reliability
If copper is used as the interconnect material, then the resistance is reduced and thermal conductivity is enhanced, but copper diffusion into the group III-V semiconductor device must be prevented
Solution Approach 1:
The patent introduces diffusion barrier layers (tantalum, tungsten, or titanium nitride) as intermediary layers between the copper interconnect and the group III-V semiconductor device. These barrier layers act as mediators that prevent copper atoms from diffusing into the semiconductor while maintaining electrical continuity and thermal management.
Solution Approach 2:
The patent employs a composite multi-layer structure consisting of adhesion layers (titanium or chromium), diffusion barrier layers (tantalum, tungsten, or titanium nitride), and copper interconnect layers. This composite structure combines the advantages of each material to achieve low resistance, high thermal conductivity, and prevention of copper diffusion into the semiconductor device.
4Area of moving object
If the line width of the metal line is reduced to increase integration density, then the current density carried by the metal line increases, but the resistance of the gold metal line becomes higher
Solution Approach 1:
The patent changes the material parameter from gold to copper, which fundamentally alters the electrical and thermal properties. Copper provides lower resistance and higher thermal conductivity, directly resolving the energy loss issue while maintaining compatibility with group III-V semiconductor fabrication processes.
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 solution effectively reduces the resistance of conductive lines and enhances thermal conductivity, improving the electrical properties and reliability of group III-V semiconductor devices by ensuring the diffusion barrier layer adheres to the semiconductor device, dielectric layer, and copper wire line, thereby preventing copper diffusion.
Implementation Method 1
The diffusion barrier layer is disposed on the first adhesion layer. The second adhesion layer is disposed on the diffusion barrier layer. And the copper wire line is disposed on the second adhesion layer... keeping the copper of the copper wire line from diffusing into the group III-V semiconductor device
Implementation Method 2
The first adhesion layer is disposed on a part of the group III-V semiconductor device... ensuring the diffusion barrier layer is adhered to the group III-V semiconductor device, the dielectric layer and the copper wire line effectively
Implementation Method 3
the copper wire line is disposed on the second adhesion layer... reducing the resistance of the conductive line
Implementation Method 4
because the thermal conductive coefficient of gold is small, the thermal conductive property of the high speed semiconductor device is affected... enhancing thermal conductivity
Data Source
AI summary
An interconnect of the group III-V semiconductor device and the fabrication method for making the same are described. The interconnect includes a first adhesion layer, a diffusion barrier layer for preventing the copper from diffusing, a second adhesion layer and a copper wire line. Because a stacked-layer structure of the first adhesion layer/diffusion barrier layer/second adhesion layer is located between the copper wire line and the group III-V semiconductor device, the adhesion between the diffusion barrier layer and other materials is improved. Therefore, the yield of the device is increased.