Plasma Etching Film Formation for Opening Shape Control
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Solution Overview
Problem
There is a demand for a technique that can selectively form films on required regions of a target object with high controllability, particularly to address the issue of bowing shapes formed during etching processes which affect the uniformity and accuracy of pattern transfer in electronic device manufacturing.
Innovation Solution
A method involving anisotropic etching of a target layer using a mask with a fluorocarbon-based gas, followed by a sequence of processes including the supply of an organic-containing aminosilane-based gas and oxygen-containing gas to form a film on the inner surface of the opening, while using backflow prevention gases to prevent reaction product deposition in gas supply lines and suppress backflow, ensuring uniform film thickness across regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If anisotropic etching is performed using fluorocarbon-based gas, then etching speed and anisotropy are improved, but deposit formation on the opening inner surface causes bowing shapes
Solution Approach 1:
The patent converts the harmful deposit formation into a beneficial protective layer. The fluorocarbon-based gas that causes bowing shapes is used to form a protective film on the opening inner surface before etching. This protective film prevents direct plasma interaction with the opening, eliminating the bowing shape problem while maintaining etching efficiency.
Solution Approach 2:
The patent performs preliminary film formation on the opening inner surface before the etching process. By pre-coating the opening with a protective film made from fluorocarbon-based gas, the system prepares the surface to resist plasma damage during subsequent etching, preventing deposit formation and bowing shapes.
2Productivity
If plasma processing is performed to form films, then film formation speed is improved, but temperature non-uniformity causes thickness non-uniformity
Solution Approach 1:
The patent changes the processing parameters by performing film formation without plasma, at lower temperatures. This parameter change allows the film to form uniformly across the substrate surface without the temperature non-uniformity issues that plague plasma-based film formation, while still achieving adequate film formation speed.
3Adaptability or versatility
If multiple gases are supplied through intersecting pipelines, then process flexibility is improved, but reaction products deposit in gas supply lines
Solution Approach 1:
The patent segments the gas supply system into separate, non-intersecting pipelines for different gases. This segmentation prevents reactive gases from mixing in the supply lines, eliminating reaction product deposition while maintaining the ability to supply multiple gases through dedicated separate pathways.
Solution Approach 2:
The patent introduces inert backflow prevention gases as intermediaries in the gas supply system. These inert gases are supplied through the same pipelines as reactive gases and act as barriers to prevent direct contact between reactive gases, thereby preventing reaction product formation in the supply lines while maintaining system flexibility.
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 method effectively reduces bowing shapes on the inner surface of openings, allowing for uniform film formation and improved controllability in film thickness, thereby enhancing the precision and uniformity of the etching process.
Implementation Method 1
plasma of a first gas is generated within a processing vessel of a plasma processing apparatus
Implementation Method 2
anisotropically etching the etching target layer through the opening
Implementation Method 3
the film is formed on the inner surface of the opening by repeating a sequence comprising: a first process of supplying a second gas into the processing vessel
Implementation Method 4
a third process of generating plasma of a third gas containing an oxygen atom within the processing vessel
Implementation Method 5
plasma of a third gas containing an oxygen atom
Data Source
AI summary
A method includes anisotropically etching an etching target layer of a target object through an opening of the target object by generating plasma of a first gas within a processing vessel in which the target object is accommodated; and then forming a film on an inner surface of the opening by repeating a sequence comprising: a first process of supplying a second gas into the processing vessel; a second process of purging a space within the processing vessel; a third process of generating plasma of a third gas containing an oxygen atom within the processing vessel; and a fourth process of purging the space within the processing vessel. The first gas contains a carbon atom and a fluorine atom. The second gas contains an aminosilane-based gas. The etching target layer is a hydrophilic insulating layer containing silicon. Plasma of the first gas is not generated in the first process.