SiO2 Vapor Etching with DC Electric Field Rate Control
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Solution Overview
Problem
Existing vapor etching methods for SiO2 films in semiconductor manufacturing struggle to achieve high-accuracy etching, particularly at the atomic layer level, due to difficulties in adjusting the etching rate within a desired range, leading to impaired processing yield.
Innovation Solution
A semiconductor manufacturing apparatus that uses a DC electric field to control the etching of SiO2 films by attracting charged particles in a liquid phase layer on the film surface, while repelling others, without plasma, by applying DC power to an electrode inside the processing chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional vapor etching with mixed gas of HF and alcohol is used, then etching can be performed on SiO2 film, but the etching rate cannot be adjusted with high accuracy
Solution Approach 1:
The invention changes the physical state parameter of the processing gas from gas phase to liquid phase by condensing it on the wafer surface. This phase change enables precise control of the etching rate through temperature management of the liquid layer, resolving the contradiction between etching accuracy and ease of rate control.
Solution Approach 2:
The invention employs periodic pulsing of the liquid processing gas supply and uses cyclic temperature control to manage the liquid layer thickness. This periodic action allows precise adjustment of etching rate while maintaining high etching accuracy, addressing both control ease and precision requirements.
2Speed
If temperature and pressure parameters are changed to adjust etching rate, then etching speed can be modified, but these parameters are difficult to change at high speed
Solution Approach 1:
The invention switches from controlling gas phase parameters (temperature and pressure) to controlling liquid phase properties. The liquid processing gas can be rapidly deposited and removed by controlling valve opening/closing, enabling fast etching rate adjustment without complex temperature/pressure control systems.
Solution Approach 2:
The invention replaces the mechanical/thermal system of temperature and pressure control with a simpler fluid control system. By using liquid deposition and removal through valve control, the system achieves rapid parameter adjustment without the inertia and complexity of thermal mass changes.
3Ease of operation
If continuous etching is applied, then the process is simple to operate, but the etching amount monotonically increases without precise control
Solution Approach 1:
The invention replaces continuous etching with periodic pulsing of the liquid processing gas supply. By controlling the pulse duration, frequency, and number of cycles, the total etching amount can be precisely controlled while maintaining operational simplicity. The process remains easy to operate but achieves precise etching depth control through timed liquid deposition cycles.
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 high-accuracy etching of SiO2 films, especially at the atomic layer level, with improved processing yield and control over the etching rate through adjustable voltage application.
Implementation Method 1
supplying DC power to an electrode arranged inside the sample table to form an electric field in the first layer for etching the first film without using plasma by attracting charged particles which are contained in the first layer and capable of contributing the etching of the first film toward a lower surface of the first layer, and repulsing other particles toward an upper surface of the first layer
Data Source
AI summary
Provided is an etching apparatus or an etching method which improves a processing yield in etching a film formed of SiO2. As means therefor, a semiconductor manufacturing apparatus, which includes an introduction port through which a processing gas containing respective vapors of hydrogen fluoride and an alcohol is introduced into a processing chamber inside a processing vessel, a sample table which is arranged in the processing chamber and on which a wafer to be processed is placed on an upper surface thereof, and an electrode which is arranged inside the sample table, and, when etching a first film formed on the upper surface of the wafer, configured to apply DC power that forms an electric field on a first layer formed on the upper surface of the wafer by the processing gas, is used.