Switch-Mode Substrate Biasing for Narrow Ion Energy Control
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Solution Overview
Problem
Current plasma processing techniques struggle to achieve a narrow ion energy distribution, which is essential for precise etching and deposition in semiconductor fabrication, due to the inefficiencies and high costs associated with existing methods that attempt to control ion energy, often affecting plasma density and etch profiles.
Innovation Solution
A switch-mode power supply system that applies a DC voltage and alternately switches between two voltages to create a controlled ion energy distribution by modulating the voltage waveform, allowing for precise ion energy control without significantly impacting plasma density, using components like buck, boost, and buck-boost power technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a sinusoidal waveform is applied to the substrate to induce voltage for dielectric etching, then the substrate can attract electrons and ions for material dislodgement, but this produces a broad distribution of ion energies which limits etch profile precision
Solution Approach 1:
The patent applies periodic voltage pulses with specific timing and amplitude characteristics to the substrate. By controlling the pulse width, frequency, and amplitude, the system achieves narrow ion energy distribution while maintaining effective ion attraction for dielectric etching, resolving the contradiction between ease of operation and manufacturing precision.
2Manufacturing precision
If known techniques are used to achieve a narrow ion energy distribution, then etch profile precision may be improved, but these techniques are expensive, inefficient, difficult to control, and may adversely affect plasma density
Solution Approach 1:
The patent controls ion energy distribution by adjusting voltage pulse parameters (amplitude, width, frequency) rather than using complex hardware modifications. This approach achieves narrow ion energy distribution with simpler, more controllable equipment, reducing device complexity while maintaining manufacturing precision.
Solution Approach 2:
The system incorporates feedback mechanisms to monitor and adjust voltage pulse characteristics in real-time, enabling precise control of ion energy distribution without requiring overly complex control systems. This resolves the contradiction by providing an efficient and controllable method.
3Manufacturing precision
If known techniques are used to achieve a narrow ion energy distribution, then etch profile precision may be improved, but these techniques may adversely affect plasma density
Solution Approach 1:
The patent uses dynamic voltage pulsing that adapts to plasma conditions, maintaining narrow ion energy distribution while preserving plasma density. The system adjusts pulse characteristics in response to plasma state changes, preventing adverse effects on plasma density while achieving precise ion energy 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 enables efficient and cost-effective control of ion energy distribution, resulting in improved etch profiles and reduced energy costs by maintaining plasma density, thus enhancing the precision and efficiency of plasma processing.
Implementation Method 1
A switch-mode power supply system that applies a DC voltage and alternately switches between two voltages to create a controlled ion energy distribution by modulating the voltage waveform
Implementation Method 2
a second voltage is applied at the first node to effectuate a negative voltage at the surface of the substrate... which causes ions to be attracted toward the negatively-charged surface
Implementation Method 3
allowing for precise ion energy control without significantly impacting plasma density
Data Source
AI summary
An apparatus and method to produce a waveform. The apparatus includes a first node to couple to a substrate support and a power supply coupled to a second node wherein the power supply is configured to provide a DC voltage to set an ion-energy at a surface of the substrate. The apparatus also includes a first switch that couples the second node to the first node, and responsive to the first switch being closed, a first voltage is applied at the first node. A second switch of the power supply couples a third node to the first node, and responsive to the second switch being closed, a second voltage is applied at the first node to effectuate a negative voltage at the surface of the substrate.