Plasma Processing High Frequency Power Pulsing
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Solution Overview
Problem
Conventional plasma processing techniques face issues with maintaining optimal ion and radical densities during etching, leading to reduced etching speed and potential damage to semiconductor wafers due to high electron temperature plasma and dielectric breakdown, especially during transitions between processing steps.
Innovation Solution
A plasma processing method where either the high frequency power for plasma formation or bias potential formation repeats changes in amplitude with a predetermined repetition period, adjusting the output intensity and duty ratio to prevent excessive output intensity during step transitions, thereby controlling plasma characteristics and reducing wafer damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high frequency power is supplied continuously at high output intensity to maintain high ion density for fast etching, then etching speed is improved, but electron temperature increases causing dielectric breakdown and wafer damage
Solution Approach 1:
The patent applies periodic pulsing of high frequency power to the plasma generating electrode, creating cycles of high power (for ionization and etching) followed by low power (for electron cooling). This periodic action allows the plasma to maintain high ion density during the etching phase while reducing electron temperature during the recovery phase, preventing dielectric breakdown and wafer damage while maintaining fast etching speeds
Solution Approach 2:
The patent dynamically adjusts the output intensity and duty ratio of the high frequency power supply based on real-time plasma conditions and processing requirements. By making the power supply dynamic rather than static, the system can optimize the balance between ion density (for etching speed) and electron temperature (for wafer safety) throughout the etching process, adapting to changing conditions to maintain both high productivity and wafer integrity
2Manufacturing precision
If pulse output parameters are changed during processing step transitions to optimize etching conditions, then etching precision is improved, but output intensity deviations occur causing excessive plasma generation and wafer damage
Solution Approach 1:
The patent performs preliminary actions before processing step transitions by predicting when parameter changes will be needed and preparing the power supply in advance. The controller monitors plasma conditions and anticipates transition points, adjusting pulse width, duty ratio, or frequency gradually before the actual transition occurs. This prevents sudden output intensity deviations that would cause excessive plasma generation and wafer damage, while still achieving the desired etching precision
Solution Approach 2:
The patent implements feedback control by continuously monitoring plasma parameters (such as impedance, power absorption, or electron temperature indicators) and adjusting the pulse output parameters in real-time. When approaching a processing step transition, the feedback mechanism detects changes in plasma conditions and modulates the power supply to maintain optimal output intensity, preventing deviations that would lead to wafer damage while achieving precise etching 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
This approach suppresses the generation of high electron temperature plasma, improves processing yield, and prevents semiconductor wafer damage by maintaining suitable etching conditions during transitions between processing steps.
Implementation Method 1
supplying an electric field using first high frequency power for plasma forming into the processing chamber and forming plasma
Implementation Method 2
supplying an electric field using first high frequency power for plasma forming into the processing chamber
Implementation Method 3
supplying second high frequency power for bias potential forming to electrodes disposed within the sample stage and processing a film on a top surface of the wafer
Implementation Method 4
attracting charged particles in the plasma to the surface of the sample in the plasma
Implementation Method 5
causing the charged particles to collide with the surface of the sample
Implementation Method 6
processing a film on a top surface of the wafer
Data Source
AI summary
A plasma processing method including disposing a wafer to be processed on a sample stage disposed in a processing chamber within a vacuum vessel, supplying an electric field using first high frequency power for plasma forming into the processing chamber and forming plasma, and supplying second high frequency power for bias potential forming to electrodes disposed within the sample stage and processing a film on a top surface of the wafer. At least the first or second high frequency power repeats a change of becoming a plurality of predetermined amplitudes for predetermined periods with a predetermined repetition period. In the processing of the film, supply of the high frequency power is changed by finally increasing a predetermined magnitude of amplitude among the repetition period, ratio of the period, and amplitude of the at least the first or second high frequency power, or first decreasing a predetermined magnitude of the amplitude.