Squashed Dome Plasma Chamber for Uniform Density
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Solution Overview
Problem
Existing substrate processing systems face challenges in achieving uniform plasma density and efficient plasma generation due to the geometrical limitations of traditional plasma source chamber shapes, such as cylindrical, dome-shaped, and flat-shaped chamber members, which result in non-uniform etching and increased copper loss.
Innovation Solution
A plasma source chamber with a cylindrically-shaped sidewall, a transition member, and an injector connecting member, along with a pedestal design featuring a radio frequency electrode, lift pins, and insulators, allows for controlled and uniform plasma generation across the substrate, reducing plasma residence time and copper loss by optimizing coil placement and gas injection configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a dome-shaped chamber member is used with center and outer mounted coils, then plasma generation is achieved, but the distance between the center mounted coil and substrate is larger than between the outer mounted coil and substrate, resulting in longer plasma species residence time in the center and non-uniform plasma density
Solution Approach 1:
The chamber member uses a squashed dome shape with optimized curvature ratios instead of a traditional dome shape. The center height to low inner diameter ratio is controlled at 0.25-0.5 and center height to outer height ratio at 0.4-0.85, creating a flattened dome geometry that reduces the vertical distance from the center coil to the substrate while maintaining plasma generation efficiency and uniformity across the substrate surface.
2Strength
If a flat-shaped chamber member with thick dielectric window is used, then mechanical strength is sufficient to withstand pressure difference, but the coils are located far from the plasma, reducing mutual inductance and increasing copper loss
Solution Approach 1:
The invention adopts a squashed dome shape that allows the chamber member to maintain mechanical strength through optimized curvature geometry rather than relying on a thick flat dielectric window. This curved geometry enables the coils to be positioned closer to the plasma region, improving mutual inductance and reducing copper loss while the domed structure inherently withstands pressure differences.
Solution Approach 2:
The invention changes the geometric parameters of the chamber member from a flat configuration to a squashed dome configuration with specific height-to-diameter ratios. This parameter change allows the system to achieve both mechanical strength and reduced coil-to-plasma distance, thereby reducing energy loss while maintaining structural integrity under pressure.
3Device complexity
If a cylindrically-shaped chamber member is used, then structural simplicity is achieved, but all coils are located around the circumference, preventing adjustment of radial plasma density from center to outer edge
Solution Approach 1:
The invention transitions from a cylindrical chamber member to a squashed dome shape. This geometric modification enables independent positioning of center and outer coils at different vertical heights, allowing radial plasma density control while maintaining relatively simple structural construction through the domed geometry.
Solution Approach 2:
The squashed dome shape introduces a vertical dimension for coil positioning that is not present in a cylindrical configuration. By utilizing the vertical height variation in the domed structure, the system can independently control plasma density at different radial positions (center vs. outer edge) through differential coil placement, adding a degree of freedom for plasma control.
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 provides improved etching uniformity, reduced substrate damage, and increased efficiency by ensuring uniform plasma density and reduced magnetic field loss, leading to enhanced product yields and reduced equipment footprint.
Implementation Method 1
radio frequency (RF) plasma may be generated to activate chemical reactions
Implementation Method 2
The RF plasma may be an inductively coupled plasma (ICP) or a transformer coupled plasma (TCP)
Implementation Method 3
The RF plasma may be an inductively coupled plasma (ICP) or a transformer coupled plasma (TCP)
Data Source
AI summary
A chamber member of a plasma source is provided and includes a sidewall, a transition member, a top wall and an injector connecting member. The sidewall is cylindrically-shaped and surrounds an upper region of a substrate processing chamber. The transition member is connected to the sidewall. The top wall is connected to the transition member. The injector connecting member is connected to the top wall, positioned vertically higher than the sidewall, and configured to connect to a gas injector. Gas passes through the injector connecting member via the gas injector and into the upper region of the substrate processing chamber. A center height to low inner diameter ratio of the chamber member is 0.25-0.5 and/or a center height to outer height ratio of the chamber member is 0.4-0.85.