Etching Method for Silica-Based Residue Removal
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Solution Overview
Problem
Conventional methods for removing silica-based residues in semiconductor manufacturing processes often damage block oxide films due to the high reactivity of HF and NH3 gases during heat treatment, leading to etching of the CVD-SiO2 films.
Innovation Solution
A two-stage etching residue removal method involving the supply of HF, H2O, or alcohol gases to selectively etch silica-based residues, followed by heat treatment in an inert gas atmosphere to remove fluorine and base components, thereby preventing damage to the block oxide film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If HF gas and NH3 gas are used to remove silica-based residue by heat treatment, then the residue removal efficiency is improved, but the block oxide film and CVD-SiO2 film are damaged due to high reactivity
Solution Approach 1:
The patent applies preliminary action by performing a selective etching process before heat treatment. HF gas is first supplied to chemically etch and remove the silica-based residue, converting it to volatile compounds. Only after the residue is removed does the patent proceed to heat treatment, thereby avoiding damage to the block oxide film and CVD-SiO2 film that would occur if heat treatment were applied directly to remove the residue.
Solution Approach 2:
The patent employs parameter changes by controlling the timing and sequence of gas supply and temperature adjustment. HF gas is supplied at lower temperatures for selective etching, then the temperature is increased for heat treatment only after residue removal. This dynamic parameter control ensures high residue removal efficiency while preventing film damage through staged process conditions.
2Manufacturing precision
If conventional heat treatment is applied to remove residue, then residue removal is achieved, but selectivity between silica-based residue and block oxide film is lost
Solution Approach 1:
The patent uses HF gas as an intermediary substance that selectively reacts with silica-based residue through chemical etching to form volatile fluorosilicate compounds. This intermediary chemical reaction provides high selectivity for residue removal while leaving the block oxide film and CVD-SiO2 film intact, as HF has different reactivity toward these materials under the controlled process conditions.
Solution Approach 2:
The patent applies local quality by creating different chemical environments for different regions of the substrate. The selective etching process targets specifically the silica-based residue regions through HF gas reaction, while the block oxide film and CVD-SiO2 film regions remain unaffected due to their different chemical properties. This localized chemical interaction achieves high selectivity without unwanted etching of other film layers.
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 effectively removes etching residues without damaging the block oxide or CVD-SiO2 films, ensuring high selectivity and preventing unwanted etching during the residue removal process.
Implementation Method 1
selectively etching the silica-based residue by supplying an HF gas, an H2O gas or an alcohol gas to a target substrate having the SiO2 film
Implementation Method 2
removing an etching residue caused by the selectively etching the silica-based residue, after the selectively etching the silica-based residue. The removing an etching residue includes a first process of supplying an H2O gas or an alcohol gas to the target substrate and a second process of heating the target substrate after the first process
Data Source
AI summary
An etching method of etching a silica-based residue containing a base component formed in an SiO2 film, includes selectively etching the silica-based residue by supplying an HF gas, an H2O gas or an alcohol gas to a target substrate having the SiO2 film, on which the silica-based residue is formed, and removing an etching residue caused by the selectively etching the silica-based residue, after the selectively etching the silica-based residue. The removing an etching residue includes a first process of supplying an H2O gas or an alcohol gas to the target substrate and a second process of heating the target substrate after the first process.