Silicon Compound Dry Etching Gas Mix for Low Halogen Residue
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Solution Overview
Problem
Existing dry etching methods using iodinated or brominated fluorocarbon compounds often result in residual iodine or bromine atoms on semiconductor substrates, which can affect device characteristics and require stringent cleaning processes, posing challenges in advanced material processing.
Innovation Solution
A dry etching method combining iodinated or brominated fluorocarbon compounds with unsaturated fluorocarbons and unsaturated hydrofluorocarbons, along with an oxidizing gas, to control the generation and deposition of ion species, thereby reducing the amount of residual iodine or bromine atoms on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If iodinated or brominated fluorocarbon compounds are used as etching gas, then etching selectivity and pattern shape control are improved, but residual iodine or bromine atoms remain on the substrate affecting device characteristics
Solution Approach 1:
The patent introduces unsaturated fluorocarbon and unsaturated hydrofluorocarbon as intermediary substances that react with iodine or bromine atoms during plasma etching. These intermediaries form volatile compounds with the halogen atoms, enabling their removal from the substrate surface without affecting the etching selectivity provided by the iodinated or brominated fluorocarbon compounds.
Solution Approach 2:
The patent modifies the chemical composition parameters of the etching gas by adding unsaturated fluorocarbon and unsaturated hydrofluorocarbon to the iodinated or brominated fluorocarbon compound. This parameter change enables the system to maintain the beneficial etching properties while introducing new chemical pathways for halogen atom removal.
2Manufacturing precision
If unsaturated fluorocarbon is used to generate CF2 radicals or CF radicals for preventing excessive etching, then lateral wall protection is improved, but it becomes difficult to control the ratio of CF3 ions to radical species
Solution Approach 1:
The patent creates a composite gas mixture containing iodinated or brominated fluorocarbon compound, unsaturated fluorocarbon, and unsaturated hydrofluorocarbon. This composite approach allows the system to leverage the lateral wall protection from CF2/CF radicals while the iodinated/brominated component provides controlled CF3 ion generation for anisotropic etching.
Solution Approach 2:
The patent optimizes the concentration ratios of different gas components to achieve the desired balance between CF3 ions and radical species. By adjusting the parameters of gas flow rates and partial pressures, the system maintains both sufficient etching rate and selectivity ratio.
3Reliability
If stringent cleaning processes are implemented to remove residual iodine or bromine atoms, then device characteristics are improved, but processing time and complexity increase
Solution Approach 1:
The patent performs the removal of iodine or bromine atoms during the etching process itself rather than requiring a separate post-etching cleaning step. The unsaturated fluorocarbon and hydrofluorocarbon continuously react with halogen atoms throughout etching, preventing their accumulation and eliminating the need for additional cleaning time.
Solution Approach 2:
The patent merges the etching function and the halogen atom removal function into a single integrated process. By combining iodinated/brominated fluorocarbon (for etching) with unsaturated fluorocarbon and hydrofluorocarbon (for halogen atom reaction), the system achieves both etching and cleaning functions simultaneously.
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 suppresses the presence of residual iodine or bromine atoms on the substrate to levels below 1×10^11 atoms/cm², enhancing etching selectivity and reducing the need for extensive cleaning steps, while maintaining precise etching control.
Implementation Method 1
a dry etching method for etching a silicon compound film on a substrate, which comprises: plasmatizing a dry etching agent; and etching the silicon compound film with the plasmatized dry etching agent
Implementation Method 2
when an unsaturated fluorocarbon having an unsaturated bond and an unsaturated hydrofluorocarbon having an unsaturated bond are used in combination with an iodinated fluorocarbon compound or a brominated fluorocarbon compound, it is possible to suppress the amount of iodine atoms or bromine atoms remaining on the substrate
Data Source
AI summary
The present disclosure is directed to a dry etching method for a substrate having a silicon compound film, including: plasmatizing a dry etching agent; and etching the silicon compound film with the plasmatized dry etching agent through a mask formed with a predetermined opening pattern on the silicon compound film, wherein the dry etching agent contains the following first to fourth gases; the first gas is at least one compound selected from the group consisting of iodinated fluorocarbon compounds and brominated fluorocarbon compounds; the second gas is an unsaturated fluorocarbon represented by CnFm; the third gas is an unsaturated hydrofluorocarbon represented by CxHyFz; and the fourth gas is an oxidizing gas.