Switch-Mode Waveform Generation for Narrow Ion Energy Distribution
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Solution Overview
Problem
Current plasma processing techniques for semiconductor fabrication face challenges in achieving a narrow ion energy distribution, as sinusoidal waveforms induce broad ion energy distributions, leading to inefficient etch profiles and adverse effects on plasma density, making existing methods costly, inefficient, and difficult to control.
Innovation Solution
A switch-mode power supply system that generates specific waveforms by combining peak, step, and ramp voltages to control ion energy distribution, using switch components and a controller to apply precise power levels and waveforms to the substrate, thereby achieving a defined ion energy distribution without significantly affecting plasma density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a sinusoidal waveform is applied to the substrate, then the substrate attracts electrons during the positive half cycle, but this induces a broad distribution of ion energies which limits the ability to achieve desired etch profiles
Solution Approach 1:
The patent applies periodic voltage pulses with specific timing and amplitude characteristics to the substrate. By controlling the duration, frequency, and amplitude of these periodic voltage applications, the system attracts electrons during specific phases while limiting ion energy spread, achieving narrow ion energy distribution despite periodic electron attraction
Solution Approach 2:
The patent dynamically changes voltage parameters (amplitude, duration, timing) to control the plasma processing outcome. By adjusting these parameters, the system optimizes both electron attraction and ion energy distribution, resolving the contradiction between quantity of substance processed and manufacturing precision
2Manufacturing precision
If known techniques are used to achieve a narrow ion energy distribution, then ion energy control is improved, but these techniques are expensive, inefficient, difficult to control, and may adversely affect plasma density
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor plasma conditions and automatically adjust voltage parameters to maintain narrow ion energy distribution. This feedback control simplifies operation while achieving precise ion energy control, avoiding the complexity of known techniques
Solution Approach 2:
The patent uses dynamic voltage adjustment where parameters change in real-time based on plasma conditions. This dynamic approach allows simple control architecture to achieve complex outcomes by adapting parameters continuously rather than requiring complex static control systems
3Stability of the object's composition
If a non-varying voltage is applied to the substrate, then the voltage is uniform across the surface, but this is ineffective for dielectric substrates where a voltage across the surface is needed
Solution Approach 1:
The patent applies periodic voltage pulses to dielectric substrates, creating time-varying electric fields that penetrate the dielectric and induce surface voltages. This periodic action overcomes the ineffectiveness of DC voltage on dielectrics while maintaining controlled voltage distribution
Solution Approach 2:
The patent applies preliminary voltage pulses to charge the dielectric substrate surface before the main processing phase. This preliminary action creates the necessary surface voltage on dielectric substrates without requiring complex voltage application during the actual processing
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
The system enables precise control of ion energy distribution, improving etch profiles and plasma processing efficiency while reducing energy costs and material expenses associated with thermal management.
Implementation Method 1
a first power supply to apply a first voltage, a first switch that couples the first voltage to the first node, and responsive to the first switch being closed, a peak voltage is applied at the first node
Implementation Method 2
A second switch couples a third node to the first node, and responsive to the second switch being closed, a voltage step is applied at the first node
Implementation Method 3
a second power supply is coupled to the first node to produce a ramped voltage at the first node
Implementation Method 4
A switch-mode power supply system that generates specific waveforms by combining peak, step, and ramp voltages to control ion energy distribution
Implementation Method 5
the positive ions that impact the conductor have substantially the same energy
Data Source
AI summary
An apparatus and method to produce a waveform. The apparatus includes a first node, a first power supply coupled to a second node, a first switch that couples the second node to the first node, and responsive to the first switch being closed, a peak voltage is applied at the first node. The apparatus also includes a second switch that couples a third node to the first node, and responsive to the second switch being closed, a voltage step is applied at the first node. In addition, a second power supply is coupled to the first node to produce a ramped voltage at the first node.