Carbon Plug Plasma Deposition for 3D NAND Recess Filling
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Solution Overview
Problem
Current integrated circuit fabrication techniques face challenges in forming robust carbon plugs as etch stop layers in 3D NAND memory structures, particularly due to the limitations of directional etching and the need for multiple deposition and removal cycles, which increase manufacturing time and cost.
Innovation Solution
A single plasma deposition cycle using a mixture of hydrogen-containing reducing agents and hydrocarbon gases, such as acetylene, within a radiofrequency plasma chamber, forming a carbon plug in a recess without intermediate removal steps, which mitigates the high sticking coefficient of carbon-containing precursors and allows for even deposition at different depths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple deposition and removal cycles are used to form carbon plugs, then the carbon plug robustness is improved, but the manufacturing time and process complexity increase
Solution Approach 1:
The process segments the carbon deposition into two distinct phases within a single continuous plasma cycle: an initial high-power phase for rapid carbon filling, and a subsequent low-power phase for controlled carbon removal. This segmentation allows the system to achieve both robust carbon plug formation and time efficiency by optimizing each phase's parameters independently.
Solution Approach 2:
The invention implements periodic modulation of RF power during a single plasma deposition cycle. The system alternates between high-power deposition mode and low-power removal mode within the same cycle, creating a periodic action that simultaneously achieves carbon plug formation and excess carbon removal without requiring separate process cycles.
2Manufacturing precision
If multiple deposition and removal cycles are used to form carbon plugs, then the carbon plug quality is improved, but the device complexity increases
Solution Approach 1:
The system dynamically adjusts RF power levels during the deposition cycle, transitioning from high power to low power within a single cycle. This dynamic control allows the process to adapt carbon deposition and removal rates in real-time, achieving high-quality carbon plugs with precise control over carbon distribution and density without requiring multiple static process cycles.
Solution Approach 2:
The invention changes key process parameters (RF power level, gas flow rates) within a single deposition cycle to achieve different objectives at different stages. By modulating these parameters dynamically, the system optimizes both carbon deposition and removal in one continuous process, reducing overall process complexity while maintaining high manufacturing precision.
3Productivity
If high power RF plasma is used for carbon deposition, then the deposition speed is improved, but the carbon removal efficiency decreases
Solution Approach 1:
The system employs periodic modulation of RF power within a single cycle, alternating between high-power deposition phases that maximize deposition speed and low-power removal phases that optimize carbon removal efficiency. This periodic switching allows the process to capture the benefits of both high and low power conditions without requiring separate process cycles.
Solution Approach 2:
The RF power level is dynamically adjusted during the deposition cycle, transitioning from high power to enable rapid carbon deposition to low power to facilitate efficient carbon removal. This dynamic parameter control allows the system to optimize both deposition speed and removal efficiency within a single continuous process, eliminating the trade-off between these competing objectives.
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 method enables the formation of a robust carbon plug suitable for use as an etch stop layer in 3D NAND memory structures, reducing manufacturing time and cost by eliminating the need for multiple deposition and removal cycles while ensuring reliable etch stopping properties.
Implementation Method 1
a radiofrequency (RF) power source configured to form an RF plasma between the pedestal electrode and the showerhead electrode
Implementation Method 2
exposing the workpiece to a carbon-depositing plasma in a plasma processing chamber
Implementation Method 3
The carbon-depositing plasma is formed from a mixture of gasses comprising a hydrogen-containing reducing agent and a hydrocarbon gas
Data Source
AI summary
One example provides a fabrication tool comprising a chamber, a pedestal electrode and a showerhead electrode arranged in the chamber, one or more gas inlets into the chamber, a vacuum pump system, a radiofrequency (RF) power source configured to form an RF plasma between the pedestal electrode and the showerhead electrode, and a controller comprising a processor and memory. The memory comprises instructions executable by the processor to operate the flow control hardware to introduce a hydrogen-containing reducing agent and a hydrocarbon gas into the chamber, and to operate the RF power source to form a plasma between the pedestal electrode and the showerhead electrode to fully deposit a carbon plug in a recess of a workpiece positioned on a pedestal within the chamber in a single plasma deposition cycle with no intermediate carbon removal process.