Plasma Processing Apparatus Phase Control for Etching Uniformity
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Solution Overview
Problem
Plasma processing technologies face challenges in achieving uniform etching rates across a substrate due to the generation of standing waves from superimposed high frequency electric powers, leading to uneven etching rates at the center, middle, and edge portions, which complicates the achievement of consistent Critical Dimension (CD) and etching depths.
Innovation Solution
A plasma processing method using pulse waves of high frequency electric power for plasma generation and bias, with a controlled phase difference and duty ratio, is applied to suppress the generation of standing waves, ensuring a uniform plasma process by adjusting the phase shift and duty ratios of the high frequency electric powers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high frequency electric power for plasma generation and high frequency electric power for bias are superimposed, then plasma generation and bias are achieved, but a standing wave is generated causing uneven etching rate distribution across the substrate
Solution Approach 1:
The patent applies periodic pulse waves instead of continuous high frequency electric powers. By controlling the duty ratio and phase difference of pulse waves, the superposition of electric fields is optimized to prevent standing wave formation while maintaining plasma generation and bias functions, thereby achieving uniform etching rate across the substrate
Solution Approach 2:
The patent changes the parameters of the high frequency electric powers by using pulse waves with different duty ratios and phase differences. Specifically, the duty ratio of the plasma generation power is set higher than that of the bias power, and a phase difference is introduced between them. This parameter optimization suppresses standing wave generation and achieves uniform etching distribution
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 effectively controls the etching rate distribution, reducing the hot spot ratio and achieving a uniform etching process across the substrate, thereby improving the accuracy and consistency of micro-processing.
Implementation Method 1
applying a pulse wave of high frequency electric power for plasma generation
Implementation Method 2
a high frequency power source for providing high frequency electric power for plasma generation
Implementation Method 3
a pulse wave of high frequency electric power for bias whose frequency is lower than that of the high frequency electric power for plasma generation
Data Source
AI summary
A plasma processing method includes applying a pulse wave of high frequency electric power for plasma generation and a pulse wave of high frequency electric power for bias whose frequency is lower than that of the high frequency electric power for plasma generation on the mounting table; and controlling the pulse wave of the high frequency electric power for plasma generation and the pulse wave of the high frequency electric power for bias such that a predetermined phase difference is generated between the pulse wave of the high frequency electric power for plasma generation and the pulse wave of the high frequency electric power for bias, and a duty ratio of the high frequency electric power for plasma generation becomes greater than or equal to a duty ratio of the high frequency electric power for bias.