Bias Path Controller for Uniform Dry Etching
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Solution Overview
Problem
The existing dry etching technologies face challenges in achieving uniform etching when using corrosive gases like fluorocarbon and halogen gases, particularly with a quartz shower plate, leading to non-uniformity and metal contamination issues due to the inability to control RF bias current distribution effectively.
Innovation Solution
A dry etching apparatus equipped with a bias path controller (B.P.C) on the antenna electrode, which resonates with the static reactance formed by the antenna electrode's dielectric material, allowing for control of RF bias current flow to the antenna electrode and the vacuum chamber's side wall, thereby improving etching uniformity and reducing contamination risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a quartz shower plate is used instead of silicon, then corrosion resistance to corrosive gases is improved, but RF bias current distribution uniformity deteriorates
Solution Approach 1:
A bias path controller is introduced as an intermediary component between the RF bias power supply and the quartz shower plate. This controller manages the RF bias current distribution, ensuring uniformity while maintaining the corrosion resistance benefits of the quartz material. The bias path controller acts as a mediator that resolves the conflict between using corrosion-resistant quartz and achieving uniform etching.
2Productivity
If RF bias is applied to accelerate etching, then etching speed is improved, but metal contamination increases
Solution Approach 1:
The bias path controller serves as an intermediary that manages RF bias current distribution, enabling accelerated etching while preventing metal contamination by controlling the current flow paths and reducing arcing or sparking that could cause contamination.
Solution Approach 2:
The system controls RF bias parameters (current distribution, frequency, power level) to optimize the balance between etching speed and contamination prevention. By adjusting these parameters through the bias path controller, the system achieves high etching rates while maintaining clean processing conditions.
3Productivity
If high frequency is supplied to ionize gas, then plasma generation efficiency is improved, but RF bias current control difficulty increases
Solution Approach 1:
The bias path controller acts as an intermediary device that simplifies RF bias current control at high frequencies. It provides a structured path for current flow and includes control mechanisms that make high-frequency RF bias management more straightforward, reducing the complexity despite the high plasma generation efficiency requirements.
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 enables highly uniform etching even with a quartz shower plate, effectively managing RF bias current distribution to achieve consistent etching results and prevent metal contamination, enhancing the overall etching process efficiency.
Implementation Method 1
antenna electrode which is located opposite the placement unit and supplied with high frequency is supplied to ionize etching gas into a plasma
Implementation Method 2
emits VHF radiation at a frequency of 200 MHz from the antenna electrode to ionize the gas within the vacuum chamber into a plasma
Implementation Method 3
a bias path controller (B.P.C) is provided on the side of the antenna electrode. The bias path controller (B.P.C) resonates in series with the static reactance formed by the antenna electrode dielectric material
Implementation Method 4
The wafer stage includes an RF bias power supply of 4 MHz for drawing ions in order to accelerate the etching reaction
Data Source
AI summary
There is provided dry etching apparatus including a stage on which a wafer is placed, an antenna electrode, a high frequency power supply, a shower plate, and an RF bias power supply. Further, a bias path controller is provided on the side of the antenna electrode. The bias path controller resonates in series with the static reactance formed by the shower plate with respect to the frequency of the RF bias. Then, the bias path controller changes and grounds the impedance by the variable inductive reactance. With this mechanism, highly uniform etching can be achieved even if a shower plate of quartz is used for corrosive gases.