Bias Power Waveform Control for Selective Substrate Treatment
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Solution Overview
Problem
Current substrate treatment processes in semiconductor and display device manufacturing face challenges in controlling ion energy and plasma processes, leading to issues such as ion charge-up, neutral saturation, and byproduct exhaust, which affect selectivity and aspect ratio.
Innovation Solution
A substrate treatment apparatus and method utilizing a bias power supply that generates a pulsed non-sinusoidal waveform, incorporating a DC power generator with feedforward compensation and a modulator to filter the power signal, reducing overshoot and improving control over ion energy by alternating on and off periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a continuous sinusoidal bias power is applied to control ion energy, then ion energy control is achieved, but ion charge-up and neutral saturation occur leading to reduced selectivity and aspect ratio
Solution Approach 1:
The patent applies periodic pulsed bias power instead of continuous sinusoidal power. The pulse signal generator generates periodic pulse signals that switch the bias power on and off in a controlled manner. This periodic action prevents continuous ion bombardment, thereby reducing ion charge-up and neutral saturation effects while maintaining precise ion energy control during the on-periods, ultimately improving selectivity and aspect ratio in substrate treatment processes.
2Manufacturing precision
If conventional bias power supply is used, then simple control is maintained, but overshoot occurs in the bias power waveform reducing process precision
Solution Approach 1:
The patent implements a feedback control mechanism where the actual bias power waveform is monitored and compared with the target waveform. The control system adjusts the pulse signal parameters based on the difference (error) between actual and target waveforms, eliminating overshoot and ensuring precise waveform reproduction. This feedback loop maintains manufacturing precision while the structured approach keeps the increased device complexity manageable.
3Manufacturing precision
If pulsed non-sinusoidal bias power is generated with feedforward compensation, then overshoot is reduced and ion energy control is improved, but the power supply structure becomes more complex
Solution Approach 1:
The patent employs feedforward compensation where the control system pre-calculates and applies compensation signals based on the known characteristics of the power supply system and pulse signal. By anticipating and compensating for potential waveform distortions and overshoot before they occur, the system achieves precise ion energy control. This preliminary action approach, combined with feedback, manages the increased device complexity by using structured compensation algorithms rather than requiring overly complex hardware modifications.
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 solution effectively reduces ion charge-up, neutral saturation, and byproduct exhaust, enhancing selectivity and aspect ratio by precisely controlling the ion energy through the use of a pulsed non-sinusoidal bias power waveform.
Implementation Method 1
a DC power generator configured to receive the pulse signal and generate a direct-current (DC) voltage subjected to feedforward compensation based on the pulse signal
Implementation Method 2
a modulator configured to generate a power signal having a non-sinusoidal waveform using the DC voltage, and filter the power signal using the pulse signal to generate the bias power having the pulsed non-sinusoidal waveform
Implementation Method 3
The bias voltage induces a voltage on the substrate through a chuck. Controlling the voltage induced on the substrate may result in precisely controlling an ion energy incident on the substrate
Implementation Method 4
Plasma may be used in these various processes. To control ions activated by the plasma, a bias voltage is applied to an electrode in a process the chamber
Data Source
AI summary
A substrate treatment apparatus including a chamber; a lower electrode in the chamber, wherein the substrate is on the lower electrode; an upper electrode in the chamber, and above the lower electrode; a pulse signal generator configured to generate a pulse signal; and a bias power supply configured to generate bias power having a pulsed non-sinusoidal waveform using the pulse signal, and supply the generated bias power to the lower electrode, wherein the bias power supply includes a DC power generator configured to receive the pulse signal and generate a direct-current (DC) voltage subjected to feedforward compensation based on the pulse signal; and a modulator configured to generate a power signal having a non-sinusoidal waveform using the DC voltage, and filter the power signal using the pulse signal to generate the bias power having the pulsed non-sinusoidal waveform.