Deposition Gas Pressure Boosting for Tungsten Step Coverage
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Solution Overview
Problem
In high-aspect-ratio openings of memory devices, the deposition gas for forming tungsten thin films often decomposes before reaching the bottom surface, leading to reduced step coverage and increased defect rates.
Innovation Solution
A layer deposition method and apparatus where the pressure of the deposition gas is elevated beyond a predetermined charge pressure, ensuring sufficient gas reaches the bottom surface, enhancing step coverage and Unit Per Equipment Hour (UPEH) performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deposition gas is introduced at predetermined charge pressure, then gas consumption is controlled, but step coverage is reduced due to gas decomposition before reaching the bottom surface
Solution Approach 1:
The patent implements periodic pressure elevation to the deposition gas. The gas pressure is elevated to a higher pressure level during specific periods when deposition is needed, then returned to predetermined charge pressure during other periods. This periodic action ensures sufficient gas reaches the bottom surface of high-aspect-ratio openings during deposition periods while controlling overall gas consumption during non-deposition periods.
Solution Approach 2:
The patent changes the pressure parameter of the deposition gas dynamically. Instead of maintaining a constant predetermined charge pressure, the system elevates the gas pressure to a higher level during deposition operations to improve step coverage, then reduces it back to the predetermined level to control gas consumption. This parameter change allows optimization of both step coverage and gas consumption at different operational phases.
2Manufacturing precision
If gas pressure is elevated to improve step coverage, then deposition quality improves, but gas consumption increases
Solution Approach 1:
The system employs periodic pressure elevation where the deposition gas pressure is raised to a higher level only during the actual deposition process when improved step coverage is needed. During idle or non-deposition periods, the pressure is maintained at the lower predetermined charge pressure level. This periodic action pattern ensures that the energy-intensive high-pressure state is maintained only when necessary for quality deposition, thereby reducing overall gas consumption and energy loss.
Solution Approach 2:
The patent implements preliminary pressure elevation of the deposition gas before the actual deposition process begins. By elevating the gas pressure in advance during a preparation phase, the system ensures that when deposition starts, the gas is already at the optimal high pressure level for achieving good step coverage. This preliminary action prevents gas decomposition issues from the outset while allowing the system to return to lower pressure afterward, minimizing overall gas consumption.
3Manufacturing precision
If deposition gas reaches bottom surface of high aspect ratio opening, then step coverage increases, but gas decomposition occurs before reaching bottom
Solution Approach 1:
The patent changes the pressure parameter of the deposition gas to a higher level during deposition operations. This pressure elevation increases the driving force of the gas flow, enabling it to reach the bottom surface of high-aspect-ratio openings before decomposition occurs. By maintaining this elevated pressure throughout the deposition process, the system ensures complete coverage of vertical structures while preventing gas decomposition-related defects.
Solution Approach 2:
The system performs preliminary elevation of the deposition gas pressure before the gas enters the deposition zone. This preliminary pressure elevation ensures that the gas has sufficient momentum and pressure to traverse the entire length of high-aspect-ratio openings without decomposing prematurely. By establishing the correct pressure condition in advance, the system guarantees that the gas reaches the bottom surface intact, improving both step coverage and reducing defect rates.
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 elevated pressure deposition method effectively increases step coverage characteristics and UPEH of tungsten thin films, improving the reliability and reducing defect rates in semiconductor devices.
Implementation Method 1
The pressure of the deposition gas is elevated to have a pressure greater than the predetermined charge pressure, and the deposition gas having the elevated pressure is supplied to the process chamber
Data Source
AI summary
In a layer deposition method, a substrate is loaded into a process chamber. A gas filling tank is charged with a gas to a predetermined charge pressure. The pressure of the gas is elevated to a pressure greater than the predetermined charge pressure. The gas is introduced into the process chamber.