Pulsed Plasma Bias Frequency Control for Precise Feature Profiles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional plasma processes lack independent and precise control over etching and deposition, leading to imperfections such as recesses and necking in feature profiles.
Innovation Solution
The method involves generating plasma with a source power pulse and applying a bias power pulse with increasing frequency from a first to a second frequency value, allowing for precise control of ion energy distribution and independent control over deposition and etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma processes are used, then plasma deposition and etching can be performed, but independent and precise control over deposition and etching is lost, resulting in feature profile imperfections
Solution Approach 1:
The plasma process is segmented into distinct deposition and etching phases with separate power control. The source power (SP) and bias power (BP) are independently pulsed and tuned to achieve precise control over deposition and etching operations, allowing each process to be optimized separately while maintaining overall feature profile precision
Solution Approach 2:
The patent employs dynamic power modulation where the bias power frequency is varied during the etching phase (e.g., sweeping from 100 kHz to 10 MHz) to control ion energy distribution. This dynamic adjustment enables precise control over etching anisotropy and feature profile formation, directly addressing the control precision challenge
2Loss of substance
If conventional plasma processes are used, then material can be deposited or etched, but independent control over deposition and etching is insufficient, leading to material loss and feature imperfections
Solution Approach 1:
The patent uses periodic pulsing of source power and bias power to alternately perform deposition and etching operations. By controlling the pulse timing, duration, and frequency, the process minimizes material loss through selective deposition during source pulses and controlled etching during bias pulses, reducing unwanted material removal while maintaining manageable process complexity
Solution Approach 2:
The patent changes multiple process parameters including source power level, bias power level, bias power frequency, and pulse timing to independently control deposition and etching rates. This multi-parameter control approach minimizes material loss by optimizing each parameter for its specific function while keeping the overall process control systematic rather than overly complex
3Object-affected harmful factors
If conventional plasma processes are used, then etching can be performed, but ion energy control is insufficient, causing harmful effects such as recesses and necking in feature profiles
Solution Approach 1:
The patent implements feedback control by monitoring the ion energy distribution through bias power frequency sweeping and adjusting the bias power parameters accordingly. This feedback mechanism ensures ion energy remains within optimal ranges to prevent harmful effects like recesses and necking, directly reducing feature profile damage while maintaining effective ion energy control
Solution Approach 2:
The patent performs preliminary deposition of protective layers during source power pulses before etching begins. This preliminary action creates a protective coating on feature surfaces that prevents ion-induced damage during subsequent etching, reducing harmful effects on feature profiles while the bias power is tuned to control ion energy appropriately
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 precise control over ion energy, reducing material loss and improving feature profiles by maintaining ion energy peaks below threshold energies, thus enhancing etch selectivity and reducing imperfections.
Implementation Method 1
generating plasma within a process chamber with a source power (SP) pulse
Implementation Method 2
applying a bias power (BP) pulse to a substrate holder within the process chamber, a frequency of the BP pulse increasing from a first frequency value to a second frequency value during the BP pulse
Implementation Method 3
forming a passivation layer over the first fin with an ion-assisted deposition
Data Source
AI summary
A method for a plasma process includes generating plasma within a process chamber with a source power pulse and applying a bias power pulse to a substrate holder within the process chamber. A frequency of the bias power pulse increases from a first frequency value to a second frequency value during the bias power pulse. The bias power pulse occurs after the source power pulse.