Plasma Etching Bias Timing for Stable Ion Motion Control
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Solution Overview
Problem
Existing substrate processing apparatuses face challenges in effectively managing the motion of ions during plasma etching processes, particularly when plasma density changes, which can affect the precision and efficiency of semiconductor manufacturing.
Innovation Solution
The apparatus incorporates a source power supply and a bias voltage supply that generate pulsed power and voltage waveforms, respectively, with controlled timing relationships to manage ion motion and plasma density adjustments, including specific power and voltage levels and timing intervals to synchronize their outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the source power supply continuously excites plasma at high power levels, then plasma density is maintained, but ion motion becomes uncontrolled and processing precision deteriorates
Solution Approach 1:
The source power supply operates in periodic pulse cycles, alternating between on-time (exciting plasma to maintain density) and off-time (allowing ion motion to settle for precision). This periodic switching resolves the contradiction by temporally separating the requirements for high plasma density and controlled ion motion.
Solution Approach 2:
Before each plasma excitation pulse, a bias voltage is applied to the substrate in advance to pre-control ion motion and accumulation. This preliminary bias voltage application ensures that when plasma is excited, ions are already positioned and prepared for precise processing, preventing uncontrolled ion behavior.
2Manufacturing precision
If the bias voltage supply adjusts voltage levels rapidly to control ion motion, then ion motion control improves, but system stability deteriorates due to timing synchronization issues
Solution Approach 1:
The system incorporates timing feedback mechanisms where the controller monitors the actual timing of source power and bias voltage pulses, adjusting their relative phases and durations to maintain optimal synchronization. This feedback ensures stable and repeatable ion motion control across varying process conditions.
Solution Approach 2:
The bias voltage supply dynamically adjusts its voltage levels and timing based on real-time process conditions, allowing the system to adapt to changing plasma characteristics while maintaining stable operation through coordinated control of multiple dynamic parameters.
3Productivity
If pulsed power and voltage waveforms are used to control ion motion, then processing efficiency improves, but process complexity increases due to multiple power supplies and timing coordination
Solution Approach 1:
The controller serves multiple functions by coordinating both the source power supply and bias voltage supply, managing pulse timing, voltage levels, and cycle durations from a single control unit. This multi-functionality reduces the need for separate dedicated control systems for each component.
Solution Approach 2:
The system merges the control of source power and bias voltage into a unified pulsed operation scheme, where both power supplies are synchronized to work together in coordinated pulse cycles. This combining of control strategies simplifies the overall process architecture despite the presence of multiple power supplies.
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 enhances the precision and efficiency of substrate processing by effectively controlling ion motion and plasma density, improving the quality and consistency of semiconductor manufacturing processes.
Implementation Method 1
a source power supply configured to generate a source power such that a power level of an output of the source power pulses, thereby exciting plasma in the chamber
Implementation Method 2
In general, in order to create plasma, an electromagnetic field is created in the inner space of a chamber, and the electromagnetic field excites a process gas provided in the chamber to a plasma state
Implementation Method 3
a bias voltage supply that is connected to the support member and is configured to generate a bias voltage such that a voltage level of an output of the bias voltage supply pulses
Implementation Method 4
The etching process may be performed by colliding ion particles contained in the plasma with the substrate
Data Source
AI summary
A substrate processing apparatus according to an exemplary embodiment includes a chamber, a source power supply that provides power for exciting plasma in a form in which the power level pulses, a support member that is disposed inside the chamber and supports a substrate, and a bias voltage supply that is connected to the support member and supplies a voltage for bias, and the power level of the output of the source power supply falls at a power fall time, and the voltage level of the output of the bias voltage supply rises from a control voltage level to a reference voltage level at an end time, and the end time is positioned later than the power fall time by a margin time.