Tetrahedral Amorphous Carbon Layer Deposition for Thermal Stability
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Solution Overview
Problem
Current semiconductor processing methods for forming amorphous carbon layers in semiconductor wafers face challenges such as low hardness, low temperature stability, and susceptibility to degradation during thermal treatments, limiting their effectiveness in high-temperature processes and chemical mechanical polishing.
Innovation Solution
The use of highly ionized sputtering (HIS) to deposit tetrahedral amorphous carbon (ta-C) layers with a high sp3-hybridized carbon content and low hydrogen content, enabling the formation of dense, hard, and high-temperature stable diamond-like carbon (DLC) films that can withstand annealing temperatures up to 1100°C and serve as diffusion barriers, electrical isolators, or CMP stop layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional sputtering or CVD methods are used to deposit amorphous carbon layers, then the deposition process is simple and cost-effective, but the resulting layers have low hardness, low density, and poor thermal stability
Solution Approach 1:
The patent applies highly ionized sputtering (HIS) which fundamentally changes the deposition parameters compared to conventional sputtering or CVD. The high ionization degree of the sputtered material (achieved through high power impulse magnetron sputtering or similar HIS techniques) transforms the deposition mechanism, enabling formation of dense, hard ta-C layers with sp3 fraction >0.4 that can withstand annealing up to 1100°C, thus resolving the hardness-thermal stability limitation of conventional methods
Solution Approach 2:
The patent creates a composite-like structure within the amorphous carbon layer by achieving a high fraction of sp3-hybridized carbon bonds (>40%) alongside controlled hydrogen content (<10%). This sp3-rich amorphous structure mimics the hardness and thermal stability of crystalline diamond while maintaining the amorphous phase's versatility, effectively creating a diamond-like carbon (DLC) material with superior properties
2Reliability
If amorphous carbon layers are used in semiconductor processing, then they can serve as diffusion barriers and electrical isolators, but they degrade during thermal treatments above their limited temperature stability
Solution Approach 1:
The patent achieves thermal stability up to 1100°C by changing the carbon layer composition parameters: maintaining very low hydrogen content (<10 at.%) and high sp3-hybridized carbon fraction (>40%). This parameter optimization prevents hydrogen outgassing and structural collapse during thermal treatment, allowing the layer to serve as a reliable diffusion barrier and electrical isolator through high-temperature annealing processes in FEOL semiconductor manufacturing
3Reliability
If tetrahedral amorphous carbon layers with high sp3 content and low hydrogen content are deposited using HIS, then enhanced hardness and thermal stability are achieved, but the deposition process requires highly ionized sputtering equipment and optimized parameters
Solution Approach 1:
The patent employs highly ionized sputtering with specific parameter ranges: ionization degree >50% (preferably >70%), substrate bias voltage between -50V and -200V, and deposition temperature between 20°C and 400°C. These parameter changes enable controlled formation of ta-C layers with sp3 fraction >0.4 and hydrogen content <0.1, achieving thermal stability up to 1100°C while maintaining processability in industrial sputtering equipment
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 HIS process results in DLC layers with enhanced hardness, density, and thermal stability, allowing integration into semiconductor processing for front-end of line (FEOL) processes, improving the reliability and performance of semiconductor devices.
Implementation Method 1
The use of highly ionized sputtering (HIS) to deposit tetrahedral amorphous carbon (ta-C) layers
Implementation Method 2
serve as diffusion barriers
Data Source
AI summary
According to various embodiments, a semiconductor wafer may include: a semiconductor body including an integrated circuit structure; and at least one tetrahedral amorphous carbon layer formed at least one of over or in the integrated circuit structure, the at least one tetrahedral amorphous carbon layer may include a substance amount fraction of sp3-hybridized carbon of larger than approximately 0.4 and a substance amount fraction of hydrogen smaller than approximately 0.1.