CN-121983148-A - Etching gas screening method, device and equipment

CN121983148ACN 121983148 ACN121983148 ACN 121983148ACN-121983148-A

Abstract

The invention discloses a screening method, a screening device and screening equipment for etching gas, relates to the technical field of microelectronic manufacturing etching, and aims to solve the problems of low efficiency and high cost in screening etching gas in the prior art. The method comprises the steps of constructing a plurality of initial fluorine saturation cluster models, firstly pre-screening the cluster models to obtain a plurality of target fluorine saturation cluster models and target reaction sites and target etching gases of the target fluorine saturation cluster models, then mechanically verifying the target fluorine saturation cluster models to obtain the reaction intensity degree of the target etching gases and silicon or germanium-silicon clusters in the target fluorine saturation cluster models, and finally determining the etching gases for the silicon and germanium-silicon laminated structure based on the reaction intensity degree of the target etching gases and the silicon or germanium-silicon clusters in the target fluorine saturation cluster models, thereby improving the etching gas screening efficiency and simultaneously reducing the cost.

Inventors

YU TONG
CHEN RUI

Assignees

北京知识产权运营管理有限公司
中国科学院微电子研究所

Dates

Publication Date: 20260505
Application Date: 20251222

Claims (10)

1. A method of screening an etching gas, comprising: constructing a plurality of initial fluorine saturation cluster models, wherein the initial fluorine saturation cluster models are saturated cluster models which reflect local structural characteristics of the surface of the silicon and germanium-silicon laminated material contacted with fluorine-containing etching gas molecules; Performing cluster model pre-screening on the initial fluorine saturation cluster models to obtain a plurality of target fluorine saturation cluster models, target reaction sites of the target fluorine saturation cluster models and target etching gas, wherein the cluster model pre-screening at least comprises model potential active site positioning, cluster model screening, cluster structure and etching gas molecular orbit interaction analysis and steric hindrance effect analysis; Based on target reaction sites and target etching gases of a plurality of target fluorine saturation cluster models, carrying out mechanical verification on the plurality of target fluorine saturation cluster models to obtain the reaction intensity degree of the target etching gases and silicon or germanium-silicon clusters in the plurality of target fluorine saturation cluster models, wherein the mechanical verification comprises reaction thermodynamic verification and reaction kinetic verification; And determining the etching gas for the silicon and germanium-silicon laminated structure based on the reaction intensity degree of the target etching gas and the silicon or germanium-silicon clusters in the target fluorine saturation cluster model.
2. The method of claim 1, wherein constructing a plurality of initial fluorine saturation cluster models comprises: Constructing a plurality of original fluorine saturation cluster models based on orientations of exposed surfaces of the silicon and germanium silicon layers in an etching process, wherein the plurality of original fluorine saturation cluster models comprise a plurality of silicon cluster models with different numbers of silicon atoms and a plurality of germanium silicon cluster models with different numbers of silicon and germanium atoms; calculating bond dissociation energy of various chemical bonds in a plurality of original fluorine saturation cluster models, determining the minimum atomic number which does not obviously change with the increase of the atomic numbers in the two clusters at the beginning of bond dissociation, and taking the minimum atomic number as the total number of silicon atoms in a silicon cluster model and the total number of germanium and silicon atoms in a germanium-silicon cluster model; And constructing a silicon cluster model saturated by fluorine atoms according to the orientation of the exposed surface of the silicon layer and the total number of silicon atoms, and constructing a germanium-silicon cluster model saturated by fluorine atoms according to the orientation of the exposed surface of the germanium-silicon layer and the total number of germanium-silicon atoms, so as to obtain a plurality of initial fluorine-saturated cluster models.
3. The method for screening etching gas according to claim 1, wherein the performing cluster model pre-screening on the plurality of initial fluorine saturation cluster models to obtain a plurality of target fluorine saturation cluster models and target reaction sites and target etching gas of the plurality of target fluorine saturation cluster models comprises: Analyzing the electron population of the initial fluorine saturation cluster models, positioning potential active sites of the initial fluorine saturation cluster models, and taking a model with the positive charge value of the atomic surface of the initial fluorine saturation cluster models larger than a preset value as a target fluorine saturation cluster model to obtain potential active sites for the target fluorine saturation cluster models and the target fluorine saturation cluster models; performing orbit interaction analysis on the cluster structures of the target fluorine saturation cluster models and etching gas molecules, determining the orbit of the potential active site to participate in the reaction, and taking etching gas which is more likely to react with germanium silicon and is not likely to react with silicon as target etching gas; and carrying out steric hindrance effect analysis on the plurality of target fluorine saturation cluster models after orbit interaction analysis, and removing potential active sites which cannot react due to steric hindrance to obtain target reaction sites.
4. The method for screening etching gas according to claim 3, wherein the positioning analysis is performed on the electronic layouts of the plurality of initial fluorine saturation cluster models, the potential active sites of the plurality of initial fluorine saturation cluster models are positioned, the model with the atomic surface positive charge value larger than the preset value in the plurality of initial fluorine saturation cluster models is used as the target fluorine saturation cluster model, and the potential active sites for the plurality of target fluorine saturation cluster models and the plurality of target fluorine saturation cluster models are obtained, and the method comprises: Performing geometric structure optimization on the initial fluorine saturation cluster models to obtain a plurality of intermediate fluorine saturation cluster models, wherein each model structure in the intermediate fluorine saturation cluster models is in a stable state, and the charge energy is the minimum value; Performing natural population analysis on the plurality of intermediate fluorine saturation cluster models to obtain net charge data of each silicon and germanium atom in the plurality of intermediate fluorine saturation cluster models; Taking a model with the positive charge value of the atomic surface of the atoms in the plurality of intermediate fluorine saturation cluster models larger than a preset value as a target fluorine saturation cluster model to obtain a plurality of target fluorine saturation cluster models; and taking the silicon atoms and germanium atoms with highest positive charge density in the target fluorine saturation cluster model as potential active sites.
5. The method for screening etching gas according to claim 3, wherein the analyzing the orbital interaction between the cluster structures of the plurality of target fluorine saturation cluster models and the etching gas molecules to determine the orbitals of the reaction at the potential active sites, using the etching gas which is more reactive with germanium silicon and is less reactive with silicon as the target etching gas comprises: Performing natural bond orbit analysis on a plurality of target fluorine saturation cluster models to obtain transfer quantity of lone pair electrons of fluorine atoms to silicon and germanium empty orbits, wherein the natural bond orbit analysis comprises analysis of each chemical bond type, interaction of electrons and empty orbits, bond level of each chemical bond and charge transfer paths in a cluster; Front line molecular orbit analysis is carried out on the target fluorine saturation cluster models to obtain the highest occupied molecular orbit and the lowest unoccupied molecular orbit of the target fluorine saturation cluster models and etching gas molecules; Performing orbit overlapping population analysis on the target fluorine saturation cluster models, and determining overlapping integration of the highest occupied molecular orbit and the lowest unoccupied molecular orbit of etching gas molecules when the etching gas molecules attack the potential reaction sites in the target fluorine saturation cluster models; And determining etching gas which is more likely to react with the germanium silicon and is not likely to react with the silicon based on overlapping integral of the highest occupied molecular orbit and the lowest unoccupied molecular orbit of etching gas molecules in the target fluorine saturation cluster model, and taking the etching gas which is more likely to react with the germanium silicon and is not likely to react with the silicon as the target etching gas.
6. The method for screening etching gas according to claim 3, wherein said analyzing the steric hindrance effect of the plurality of target fluorine saturation cluster models after the orbit interaction analysis, excluding potential active sites that cannot react due to steric hindrance, and obtaining the target reaction sites, comprises: Calculating steric hindrance parameters of a plurality of target fluorine saturation cluster models, wherein the steric hindrance parameter calculation at least comprises the steps of calculating the minimum steric hindrance radius and the maximum steric hindrance radius of steric hindrance groups around the potential active site, wherein the minimum steric hindrance radius represents that the space around the site is more loose, etching gas molecules are easier to approach, and the maximum steric hindrance radius represents that the space around the site is more crowded, and the etching gas molecules are harder to approach; And drawing Van der Waals surfaces of clusters of the target fluorine saturation cluster model by using visualization software, representing charge distribution by using different colors, judging whether potential active sites are wrapped by Van der Waals surfaces of surrounding fluorine atoms, and taking the potential active sites as the target reaction sites if the potential active sites are completely shielded.
7. The method for screening etching gas according to claim 1, wherein mechanically verifying the plurality of target fluorine saturation cluster models based on target reaction sites of the plurality of target fluorine saturation cluster models and the target etching gas to obtain reaction intensity of the target etching gas and silicon or germanium-silicon clusters in the plurality of target fluorine saturation cluster models, comprises: Based on target reaction sites of the target fluorine saturation cluster models and target etching gas, carrying out reaction thermodynamic analysis on the target fluorine saturation cluster models to obtain reaction enthalpy change and Gibbs free energy change of the target etching gas and the target fluorine saturation cluster model groups; based on target reaction sites and target etching gases of a plurality of target fluorine saturation cluster models, carrying out reaction dynamics analysis on the plurality of target fluorine saturation cluster models, and searching a transition state structure in a dynamics reaction process by adopting a transition state searching method to obtain reaction energy barriers of the target etching gases and the plurality of target fluorine saturation cluster model groups; And determining the reaction intensity degree of the target etching gas and the silicon or germanium-silicon clusters in the target fluorine saturation cluster model based on the reaction enthalpy change, the Gibbs free energy change and the reaction energy barrier of the target etching gas and the target fluorine saturation cluster model groups.
8. The method of claim 1, wherein determining the etching gas for the silicon and germanium-silicon stacked structure based on the reaction strength of the target etching gas with silicon or germanium-silicon clusters in the plurality of target fluorine saturation cluster models, comprises: comparing the difficulty of different etching gases in the reaction with the germanium-silicon clusters, and taking the etching gas which is easier to chemically react with various germanium-silicon cluster structures as an alternative etching gas; And comparing the physical quantity difference of the alternative etching gas when reacting with the silicon cluster and the germanium-silicon cluster, and taking the etching gas with the comparison physical quantity difference larger than a target value for the silicon cluster and the germanium-silicon cluster as the etching gas of the silicon-germanium-silicon laminated structure, wherein the physical quantity at least comprises energy barrier, enthalpy change and Gibbs free energy change.
9. A screening apparatus for etching gas, comprising: The system comprises a cluster model construction module, a cluster model generation module and a model generation module, wherein the model construction module is used for constructing a plurality of initial fluorine saturation cluster models, and the plurality of initial fluorine saturation cluster models are saturated cluster models which reflect local structural characteristics of the surface of a silicon and germanium-silicon laminated material contacted with fluorine-containing etching gas molecules; The cluster model pre-screening module is used for carrying out cluster model pre-screening on a plurality of initial fluorine saturation cluster models to obtain a plurality of target fluorine saturation cluster models, target reaction sites of the target fluorine saturation cluster models and target etching gas, wherein the cluster model pre-screening module at least comprises model potential active site positioning, cluster model screening, cluster structure and etching gas molecular orbit interaction analysis and steric effect analysis; The reaction strength determining module is used for carrying out mechanical verification on the multiple target fluorine saturation cluster models based on target reaction sites and target etching gases of the multiple target fluorine saturation cluster models to obtain the reaction strength degree of the target etching gases and silicon or germanium silicon clusters in the multiple target fluorine saturation cluster models, wherein the mechanical verification comprises reaction thermodynamic verification and reaction kinetic verification; and the etching gas determining module is used for determining the etching gas for the silicon and germanium-silicon laminated structure based on the reaction intensity degree of the target etching gas and the silicon or germanium-silicon clusters in the target fluorine saturation cluster models.
10. An electronic device, comprising: A processor; A memory for storing the processor-executable instructions; The processor is configured to execute the method for screening an etching gas according to any one of claims 1 to 8 by executing instructions in the memory.

Description

Etching gas screening method, device and equipment Technical Field The invention relates to the technical field of microelectronic manufacturing etching, in particular to a method, a device and equipment for screening etching gas. Background In the prior art, aiming at the problem of transverse etching of a Si/SiGe laminated structure in a GAA device, the traditional plasma etching method is easy to cause the loss of a silicon layer, while the traditional non-plasma etching method relies on fluorine-containing etching gas with high SiGe/Si etching selection ratio, but the currently used etching gas has few types and great potential safety hazard, and needs to introduce new etching gas urgently. For potential etching gas, an experimental method is generally adopted to screen the etching gas, and the experimental test method is low in efficiency and high in cost, restricts verification of new etching gas, and cannot promote rapid development of the GAA device. In view of this, there is a need for a more advanced etching gas screening method to solve the problems of low efficiency and high cost in screening etching gas in the prior art. Disclosure of Invention The invention aims to provide a screening method, a screening device and screening equipment for etching gas, which are used for systematically analyzing the mechanism and the reaction difficulty of the reaction of various etching gas molecules and Si/SiGe laminated structures in different chemical environments from the angles of static electronic structures, reaction dynamics and reaction thermodynamics, so that the efficiency of screening the etching gas is improved, the cost is reduced, and the problems of low efficiency and high cost in the process of screening the etching gas in the prior art are solved. In order to achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a method for screening etching gas, which may include: constructing a plurality of initial fluorine saturation cluster models, wherein the initial fluorine saturation cluster models are saturated cluster models which reflect local structural characteristics of the surface of the silicon and germanium-silicon laminated material contacted with fluorine-containing etching gas molecules; Performing cluster model pre-screening on the initial fluorine saturation cluster models to obtain a plurality of target fluorine saturation cluster models, target reaction sites of the target fluorine saturation cluster models and target etching gas, wherein the cluster model pre-screening at least comprises model potential active site positioning, cluster model screening, cluster structure and etching gas molecular orbit interaction analysis and steric hindrance effect analysis; Based on target reaction sites and target etching gases of a plurality of target fluorine saturation cluster models, carrying out mechanical verification on the plurality of target fluorine saturation cluster models to obtain the reaction intensity degree of the target etching gases and silicon or germanium-silicon clusters in the plurality of target fluorine saturation cluster models, wherein the mechanical verification comprises reaction thermodynamic verification and reaction kinetic verification; And determining the etching gas for the silicon and germanium-silicon laminated structure based on the reaction intensity degree of the target etching gas and the silicon or germanium-silicon clusters in the target fluorine saturation cluster model. Preferably, the constructing a plurality of initial fluorine saturation cluster models may include: Constructing a plurality of original fluorine saturation cluster models based on orientations of exposed surfaces of the silicon and germanium silicon layers in an etching process, wherein the plurality of original fluorine saturation cluster models comprise a plurality of silicon cluster models with different numbers of silicon atoms and a plurality of germanium silicon cluster models with different numbers of silicon and germanium atoms; calculating bond dissociation energy of various chemical bonds in a plurality of original fluorine saturation cluster models, determining the minimum atomic number which does not obviously change with the increase of the atomic numbers in the two clusters at the beginning of bond dissociation, and taking the minimum atomic number as the total number of silicon atoms in a silicon cluster model and the total number of germanium and silicon atoms in a germanium-silicon cluster model; And constructing a silicon cluster model saturated by fluorine atoms according to the orientation of the exposed surface of the silicon layer and the total number of silicon atoms, and constructing a germanium-silicon cluster model saturated by fluorine atoms according to the orientation of the exposed surface of the germanium-silicon layer and the total number of germanium-silicon atoms, so