Plasma Bias Pulse Control for Variable-Ion-Energy Etching
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Solution Overview
Problem
Existing plasma processing technologies lack the ability to efficiently control and vary the energy of ions supplied to a substrate during processing, leading to inconsistent results and limitations in etching complex film structures.
Innovation Solution
A plasma processing apparatus with a power source system that applies alternating pulses of different voltage levels to the substrate support electrode, allowing for controlled variation in ion energy delivery, including negative and positive pulses, to manage charge balance and optimize etching processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single voltage level is applied to the substrate holding electrode, then the plasma processing apparatus is simple to operate, but the ion energy supplied to the substrate cannot be varied, leading to inconsistent etching results
Solution Approach 1:
The power source system applies periodic pulse voltages with different voltage levels to the substrate holding electrode. By alternating between first and second voltage levels in different time periods, the system enables varied ion energy supply to the substrate, improving etching consistency for different film structures without requiring complex continuous voltage adjustment mechanisms
Solution Approach 2:
The system dynamically switches between different voltage levels (first and second voltage levels) applied to the substrate holding electrode during plasma processing. This dynamic voltage adjustment allows the ion energy to be varied in response to different processing requirements, enabling consistent etching results across complex multilayer films while maintaining relatively simple hardware through timed voltage switching
2Productivity
If high voltage is continuously applied to increase ion energy, then etching efficiency improves, but positive charge accumulation on the substrate increases, causing processing instability
Solution Approach 1:
The power source system alternates between applying first and second voltage levels in periodic pulses. This periodic voltage application allows ions to be drawn into the substrate during high voltage periods (maintaining etching efficiency) while providing rest periods at different voltage levels that allow positive charge to dissipate, preventing charge accumulation and maintaining processing stability
Solution Approach 2:
The system applies voltage pulses with different levels in sequence, where the alternation between first and second voltage levels preemptively counteracts positive charge accumulation. By switching voltage levels periodically, the system prevents charge buildup before it becomes problematic, maintaining both etching efficiency and charge balance stability
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
Enables precise control of ion energy for efficient etching of various film types, enhancing the ability to form precise features and etch complex multilayer films, such as those found in NAND devices, by supplying ions with varying energies and reducing positive charge accumulation on the substrate.
Implementation Method 1
The power source system is electrically connected to the electrode and configured to apply a bias voltage to the electrode to draw ions from a plasma in the chamber into the substrate on the substrate support
Implementation Method 2
A plasma processing apparatus is used in plasma processing on a substrate
Data Source
AI summary
The disclosed plasma processing apparatus is provided with a chamber, a substrate support, and a power source system. The substrate support has an electrode and configured to support a substrate in the chamber. The power source system is electrically connected to the electrode and configured to apply a bias voltage to the electrode to draw ions from a plasma in the chamber into the substrate on the substrate support. The power source system is configured to output a first pulse to the electrode in a first period and output a second pulse to the electrode in a second period after the first period, as the bias voltage. Each of the first pulse and the second pulse is a pulse of a voltage. A voltage level of the first pulse is different from a voltage level of the second pulse.