Atomic Layer Etching Using Radicalized Halogen Gases
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Solution Overview
Problem
The typical atomic layer etching method using hydrogen fluoride (HF) applies thermal impact to semiconductor substrates due to high temperature requirements, causing manufacturing defects and performance degradation, and is limited by its anisotropic properties, which are not suitable for isotropic etching processes.
Innovation Solution
An atomic layer etching method using a radicalized halogen gas, such as NF3, F2, CF4, HCl, HBr, or SF6, instead of HF, to modify the substrate surface, followed by a metal-containing precursor for surface layer removal, with processes optimized to minimize thermal impact and achieve isotropic etching at lower temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydrogen fluoride (HF) is used for atomic layer etching, then strong reactivity and surface modification capability are achieved, but anisotropic etching occurs and thermal impact damages semiconductor structures
Solution Approach 1:
The patent changes the chemical parameters by substituting HF with alternative halogen-based modification gases (such as Cl2, Br2, I2, or their derivatives) that enable isotropic etching and reduce thermal impact. This parameter change allows the etching process to proceed at lower temperatures while achieving desired etching quality without the harmful anisotropic effects of HF
Solution Approach 2:
The patent employs short-lived radical species generated through plasma or chemical reactions as temporary modification agents. These radicals (such as Cl•, Br•, I•) perform the surface modification function and then are removed in subsequent purge steps, enabling precise control without persistent harmful effects
2Adaptability or versatility
If halogen group materials are used instead of hydrogen fluoride to achieve isotropic etching, then isotropic property is improved, but high temperature heating is required which causes thermal impact and device degradation
Solution Approach 1:
The patent replaces the thermal activation mechanism with chemical activation through plasma generation or controlled chemical reactions. Instead of relying on high temperature to generate reactive halogen species, the invention uses plasma energy or controlled chemical reactions to produce the necessary radicals at lower substrate temperatures, thereby achieving isotropic etching without thermal damage
Solution Approach 2:
The patent utilizes phase transitions of halogen materials (such as sublimation of solid halogens or condensation of halogen gases) to control the delivery and reaction of modification gases. By carefully controlling these phase transitions, the process achieves effective surface modification at lower temperatures while maintaining isotropic etching properties
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
This method enables isotropic etching with reduced thermal stress on semiconductor substrates, maintaining device performance and allowing for precise control of etching processes at temperatures of 400°C or less, thereby minimizing defects and performance degradation.
Implementation Method 1
a modification process S20 of modifying a surface layer 110 of the substrate 100 by radicalizing a modification gas containing a halogen gas except hydrogen fluoride (HF) through the remote plasma generation device
Data Source
AI summary
The present invention relates to an atomic layer etching method for etching a surface of a substrate by using an atomic layer etching apparatus.The present invention provides an atomic layer etching method by using an atomic layer etching apparatus including a process chamber having a sealed process space, a gas injection unit installed at an upper side in the process chamber to inject a gas into the process space, a substrate support installed at a lower side in the process chamber and on which a substrate is seated, and a remote plasma generation device, the atomic layer etching method including: a substrate preparing process (S10) of preparing a substrate (100) on the substrate support; a modification process (S20) of modifying a surface layer (110) of the substrate (100) by radicalizing a modification gas containing a halogen gas except hydrogen fluoride (HF) through the remote plasma generation device coupled to the process chamber and supplying the radicalized modification gas onto the substrate (100) after the substrate preparing process (S10); a first purge process (S30) of purging the surface layer; a surface layer removal process (S40) of removing the surface layer (110) modified in the modification process (S20) by supplying a metal-containing precursor to the surface layer (110); and a second purge process (S50) of purging a surface of the substrate (100).