Plasma Etching RF Pulse Control for Discharge Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing plasma processing apparatuses face challenges in preventing deposition on internal components such as the chamber wall and insulator, leading to potential abnormal discharges and etching inefficiencies.
Innovation Solution
A plasma processing apparatus with a substrate support and upper electrode configuration that generates specific power and voltage levels in distinct states within a repetition period, including a first RF signal generator, a second RF signal generator, and a DC signal generator, to manage plasma potential and reduce deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If RF power levels are increased to improve etching rates, then productivity is improved, but abnormal discharges occur due to elevated plasma potential and potential differences between plasma and upper electrode surfaces
Solution Approach 1:
The patent applies periodic pulsed RF power to the lower electrode, alternating between high power states (for etching) and low power states (for plasma potential reduction). This periodic modulation allows the system to achieve high etching rates during high power phases while preventing abnormal discharges during low power phases when plasma potential is reduced, thus resolving the contradiction between productivity and reliability
Solution Approach 2:
The patent dynamically adjusts RF power levels and pulse widths based on real-time plasma conditions. By making the power delivery adaptive rather than static, the system can optimize etching performance while preventing abnormal discharges that would occur with continuously high power levels, thereby resolving the contradiction between high productivity and system reliability
2Productivity
If RF power levels are increased to improve etching rates, then productivity is improved, but shape abnormalities occur due to potential differences between plasma and upper electrode surfaces
Solution Approach 1:
The periodic pul RF power modulation creates alternating high and low power states that prevent excessive plasma potential buildup. This periodic action maintains stable plasma conditions during etching, preventing the potential differences that cause shape abnormalities while still achieving high etching rates during the high power phases
Solution Approach 2:
The system monitors plasma conditions and adjusts RF power delivery in response to detected plasma state changes. This feedback mechanism ensures that power levels are optimized for etching performance while preventing conditions that would lead to shape abnormalities, thus resolving the contradiction between productivity and manufacturing precision
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 effectively suppresses abnormal discharges and enhances etching efficiency by controlling plasma electron density and potential differences, improving etching rates and reducing shape abnormalities.
Implementation Method 1
a first RF signal generator coupled to the lower electrode and configured to generate a first RF signal
Implementation Method 2
a DC signal generator coupled to the upper electrode and configured to generate a DC signal
Implementation Method 3
a plasma processing chamber; a substrate support disposed in the plasma processing chamber
Implementation Method 4
managing plasma potential differences and electron density, enhancing the overall efficiency and precision of the plasma processing method
Data Source
AI summary
A plasma processing apparatus includes a plasma processing chamber, a substrate support disposed in the plasma processing chamber and including a lower electrode, an upper electrode disposed above the substrate support, a first RF signal generator coupled to the lower electrode and configured to generate a first RF signal, the first RF signal having a first power level during a first state in a repetition period, a second power level less than the first power level during a second state in the repetition period, and the second power level during a third state in the repetition period, and a second RF signal generator coupled to the lower electrode and configured to generate a second RF signal, the second RF signal having a third power level during the first state, a fourth power level greater than the third power level during the second state, and the third power level.