Plasma Etching Chamber Layout for Ion-to-Radical Ratio Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plasma processing devices struggle to simultaneously perform anisotropic etching through the supply of ions and radicals and isotropic etching through the supply of only radicals with high accuracy, and the relationship between pulse modulation duty ratio and radical density in pulse discharging methods is not easily clarified.
Innovation Solution
A plasma processing device with a processing chamber, radio frequency power supply, magnetic field generating mechanism, and a shielding plate that allows periodic control of the plasma generation position with respect to the shielding plate, enabling direct control of the ion-to-radical density ratio by positioning the electron cyclotron resonance region between radical and reactive ion etching regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single plasma processing device is configured to execute both anisotropic etching through supply of ions and radicals and isotropic etching through supply of only radicals, then the installation area and device cost are reduced, but the device complexity increases due to the need for selective plasma generation control
Solution Approach 1:
The plasma processing device divides the processing chamber into multiple regions using a shielding plate, creating distinct zones for anisotropic etching (where ions and radicals are supplied) and isotropic etching (where only radicals are supplied). This spatial segmentation allows a single device to perform multiple etching functions without requiring separate processing chambers or complex switching mechanisms.
2Manufacturing precision
If highly accurate anisotropic etching is executed through supply of ions and radicals, then the manufacturing precision is improved, but the control difficulty increases due to the need to precisely control radical density
Solution Approach 1:
The plasma processing device incorporates a radical density measurement mechanism that provides real-time feedback on the density of radicals in the plasma. Based on this feedback, the control unit adjusts the plasma generation conditions (such as power supply parameters) to maintain the radical density within a predetermined optimal range, thereby achieving highly accurate anisotropic etching while simplifying the control process.
3Manufacturing precision
If pulse discharging is used to control radical density in plasma etching, then the manufacturing precision is improved, but the difficulty of detecting and measuring increases due to the unclear relationship between pulse modulation duty ratio and radical density
Solution Approach 1:
The device employs a feedback control system that directly measures radical density and uses this measurement to adjust pulse modulation parameters. This closed-loop approach establishes a clear, data-driven relationship between pulse modulation duty ratio and radical density, eliminating the uncertainty inherent in open-loop pulse discharging methods and enabling precise control of radical density for high-precision etching.
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
Enables direct control of the ion-to-radical density ratio during anisotropic etching, facilitating highly accurate plasma etching processes for microstructure processing and reducing the complexity of device installation and cost.
Implementation Method 1
controls the magnetic field generating mechanism so that the electron cyclotron resonance region is positioned at a position above the shielding plate or at a position below the shielding plate
Implementation Method 2
a radio frequency power supply which supplies microwave radio frequency power for plasma generation in the processing chamber
Implementation Method 3
a shielding plate disposed above the sample stand for shielding incidence of ion onto the sample stand
Implementation Method 4
Based on the feature that the ion has its energy vertically biased to the surface of the semiconductor substrate (wafer), the anisotropic etching is executed using ion assisting reaction in which the radical reaction is facilitated by the energy only in the vertical direction
Implementation Method 5
when execution of etching parallel (lateral) to the wafer surface is required, the isotropic etching with no anisotropy is executed mainly utilizing the surface reaction with only radicals
Data Source
AI summary
A plasma processing device and method which allow control of a density ratio between ions and radicals, including a processing chamber, a radio frequency power supply which supplies microwave radio frequency power for plasma generation, a magnetic field generating mechanism which generates a magnetic field in the processing chamber, a sample stand disposed in the processing chamber, and a shielding plate disposed above the sample stand for shielding incidence of an ions onto the sample stand. The magnetic field generating mechanism includes a coil disposed around an outer periphery of the processing chamber, and a power supply connected to the coil. The mechanism allows a power supply of the magnetic field generating mechanism or the radio frequency power supply to control a plasma generating position with respect to the shielding plate, and to generate plasma by periodically changing the plasma generating position vertically with respect to the shielding plate.