C3F4-Based Etching Gas for Semiconductor Recess Formation
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Solution Overview
Problem
The high cost and limited availability of C4F6 gas, which is used for etching and forming recess portions in semiconductor devices, necessitate the development of alternative carbon and fluorine-containing gases that can provide similar etching performance without the expense.
Innovation Solution
The use of etching gases comprising molecules with a C3F4 group, where the number of carbon atoms is four or five, and additional groups containing chlorine, bromine, iodine, or oxygen, which allow for the formation of a protective fluorocarbon film during etching, mimicking the deposition rate and protective properties of C4F6 gas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If C4F6 gas is used for etching, then the deposition rate of fluorocarbon film is high and side surface protection is effective, but the unit price is expensive
Solution Approach 1:
The patent replaces expensive C4F6 gas with cheaper alternative gases (CF4, SF6, XeF2) that can be obtained at lower cost while achieving comparable etching and protection performance. This substitution directly addresses the cost issue without sacrificing the quality of side surface protection.
Solution Approach 2:
The patent modifies the chemical composition parameters of the etching gas by using alternative gases with different molecular structures but similar fluorocarbon deposition capabilities. By adjusting gas composition and process parameters, the patent achieves effective side surface protection at lower cost.
2Ease of manufacture
If alternative gases are used to replace C4F6 gas, then the cost is reduced, but the deposition rate of fluorocarbon film may decrease
Solution Approach 1:
The patent employs composite gas systems combining fluorocarbon gases (CF4, SF6) with oxygen or other modifiers to achieve both cost reduction and maintained etching productivity. The composite composition allows optimization of both deposition rate and etching speed.
Solution Approach 2:
The patent dynamically adjusts process parameters such as gas flow rate, pressure, and power during etching to compensate for differences in gas composition. This dynamic control ensures that etching productivity remains high while using cost-effective alternative gases.
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
These alternative gases enable efficient etching and protection of side surfaces in semiconductor devices, achieving a high mask selection ratio and aspect ratio of memory holes similar to C4F6, while offering a more economical solution by reducing the reliance on expensive C4F6 gas.
Implementation Method 1
a fluorocarbon film is deposited on a side surface of the film in the recess portion
Implementation Method 2
When a recess portion is formed on a film by etching using carbon and fluorine-containing gas, such as C4F6 gas
Data Source
AI summary
A manufacturing method of a semiconductor device includes etching a film using etching gas that has a first or second molecule which has a C3F4 group and in which the number of carbon atoms is four or five. Further, the first molecule has an R1 group that bonds to a carbon atom in the C3F4 group through a double bond, and the R1 group contains carbon and also chlorine, bromine, iodine, or oxygen. Further, the second molecule has an R2 group that bonds to a carbon atom in the C3F4 group through a single bond and an R3 group that bonds to the carbon atom in the C3F4 group through a single bond, the R2 group or the R3 group or both containing carbon, and both the R2 group and the R3 group containing hydrogen, fluorine, chlorine, bromine, iodine, or oxygen.