Continuous Plasma Etch Process Using Transition Gas Neutralization
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Solution Overview
Problem
In semiconductor wafer processing, the transition between different plasma etch processes often results in discontinuous plasma, leading to increased process time, arcing, and particulate contaminants, which can cause device failure and result in thinner etched stacks due to gas mixing issues.
Innovation Solution
A method and apparatus for maintaining a continuous plasma during cycles in a plasma processing chamber, where each cycle includes flowing and stopping different process gases with transition gases to neutralize components, ensuring a continuous plasma and minimizing gas mixing effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If plasma is turned off when transitioning between different etch processes, then gas mixing issues are avoided, but process time increases and arcing occurs
Solution Approach 1:
A transition gas is introduced as an intermediary substance between different process gases. The transition gas neutralizes reactive species from the first process gas before the second process gas is introduced, preventing harmful gas mixing effects while maintaining continuous plasma operation and avoiding the need to turn off the plasma between process transitions.
2Reliability
If plasma is turned off during process transitions, then gas mixing is prevented, but arcing and particulate contaminants increase
Solution Approach 1:
The transition gas acts as a mediator that chemically neutralizes reactive species from the previous process gas. This prevents uncontrolled chemical reactions and particulate formation that would occur if process gases mixed directly, thereby reducing harmful contaminants while maintaining stable plasma operation without turn-off transitions.
3Productivity
If process gases are mixed during transitions, then process simplicity is maintained, but etch stack thickness decreases due to gas mixing effects
Solution Approach 1:
The transition gas serves as a chemical buffer that neutralizes reactive species from the first process gas. This prevents the degradation of etch stack thickness that occurs when process gases mix directly, while allowing continuous plasma operation and maintaining high productivity through uninterrupted etching processes.
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 approach reduces process time, decreases particle defects, and maintains etch quality by preventing gas mixing issues, resulting in thicker and more consistent etched stacks compared to discontinuous plasma processes.
Implementation Method 1
providing a flow of a first transition gas into the process chamber, wherein the first transition gas neutralizes a component of the first process gas
Implementation Method 2
maintaining a continuous plasma during the cycle
Implementation Method 3
at least one electrode for providing power to the plasma processing chamber enclosure for sustaining a plasma
Data Source
AI summary
A method for processing a substrate in a process chamber is provided. A plurality of cycles is provided to process the substrate, wherein each cycle comprises the steps of providing a flow of a first process gas into the process chamber, stopping the flow of the first process gas into the process chamber, providing a flow of a first transition gas into the process chamber, wherein the first transition gas neutralizes a component of the first process gas, stopping the flow of the first transition gas into the process chamber, providing a flow of a second process gas into the process chamber, stopping the second process gas into the process chamber, and maintaining a continuous plasma during the cycle.