Semiconductor Layer Thickness Control via Angled Plasma Interaction
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Solution Overview
Problem
Conformal processing of high aspect ratio features in semiconductor substrates is challenging due to the limitations of direct plasmas with charged species, which are not suitable for 3D transitions, and radical sources are often remote, making it difficult to achieve uniform delivery and tunable film thickness.
Innovation Solution
A method involving a substrate support in a process chamber with a gas port, exhaust, and plasma port, where a process gas flows in one direction and plasma flows in a different direction, interacting at an angle, while the substrate is rotated to control the thickness profile of the layer by adjusting flow velocities, interaction angles, and rotation direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct plasma with charged species is used, then processing speed is improved, but conformality on 3D features deteriorates
Solution Approach 1:
The patent introduces a remote plasma source as an intermediary that generates reactive species in a separate chamber, which then flow through a transfer region to the processing chamber. This mediator approach allows the plasma to be generated remotely, creating non-directional reactive species that can conformally coat 3D features while maintaining processing efficiency.
Solution Approach 2:
The patent transitions from direct plasma (0D/1D) to remote plasma with a transfer region (3D), allowing reactive species to travel through a three-dimensional path before reaching the substrate. This dimensional change enables the plasma to wrap around 3D features conformally while maintaining processing speed.
2Use of energy by moving object
If excited species are used, then reactivity is improved, but lifetime deteriorates
Solution Approach 1:
The patent generates excited reactive species in advance in the remote plasma source, allowing them to be prepared with high reactivity before being transported to the processing chamber. This preliminary action ensures that the species maintain their reactive properties long enough to achieve conformal coating on 3D features.
Solution Approach 2:
The transfer region acts as an intermediary that protects excited species during transport, maintaining their reactivity while extending their effective lifetime. The controlled environment in the transfer region prevents premature deactivation of the excited species before they reach the substrate.
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 allows for improved control over the thickness and uniformity of layers on semiconductor substrates, enabling conformal processing of 3D features by optimizing the interaction of process gases and plasmas, thereby addressing the challenges of non-directional species delivery and film thickness uniformity.
Implementation Method 1
providing a plasma from the plasma port to the substrate in a second direction that is different from the first direction to form a layer
Implementation Method 2
providing a process gas from the gas port in a first direction such that the process gas flows across a surface of the substrate
Data Source
AI summary
Methods of forming a layer on a substrate may include providing a substrate to a process chamber, the process chamber having a gas port, an exhaust, and a plasma port disposed between the gas port and the exhaust; providing a process gas from the gas port in a first direction such that the process gas flows across the substrate; providing a plasma such that a flow of the plasma interacts with a flow of the process gas at an angle that is non-perpendicular; and rotating the substrate while providing the process gas and the plasma, wherein a thickness profile of the layer is controlled by adjusting at least one of a flow velocity of the process gas, a flow velocity of the plasma, the angle the flow of the plasma interacts with the flow of the process gas, or a direction of rotation of the substrate.