Silicon Substrate Pattern Recovery via Thermal Cleaning
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Solution Overview
Problem
In semiconductor device manufacturing, ultra-fine circuit patterns with line widths of 32 nm or less on silicon substrates are prone to foreign substance growth between patterns, leading to adhesion and collapse due to reactions with air components, making conventional wet etching processes ineffective and damaging the substrate.
Innovation Solution
A method involving a pattern recovery apparatus with a heating unit and gas processing capabilities to remove foreign substances by heating the substrate to 160°C or higher, preferably between 200°C and 500°C, and optionally using HF gas exposure to restore pattern shape, while maintaining a controlled atmosphere to prevent substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If wet cleaning process is performed to remove foreign substances, then cleaning effectiveness is improved, but patterns collapse due to surface tension and adhesion
Solution Approach 1:
The patent replaces the mechanical wet cleaning process with a thermal field-based cleaning method. By heating the substrate to 160°C or higher in a controlled atmosphere, foreign substances are removed through thermal decomposition and oxidation without liquid contact, thereby avoiding surface tension-induced pattern collapse while maintaining effective contamination removal
Solution Approach 2:
The patent employs an inert or controlled atmosphere (such as nitrogen or reduced oxygen environment) during the thermal cleaning process. This controlled atmosphere prevents unwanted chemical reactions with the ultra-fine patterns while allowing thermal decomposition of foreign substances, thus protecting pattern integrity during contamination removal
2Loss of time
If silicon substrate is left in air after etching, then processing time is reduced, but foreign substances grow between patterns causing adhesion and collapse
Solution Approach 1:
The patent performs preliminary thermal cleaning immediately after etching while the substrate is still in the processing chamber, before transferring to air environment. By heating to 160°C or higher and maintaining a controlled atmosphere during this critical transition period, foreign substance formation is prevented at the source, eliminating the need for extended processing time or air exposure
Solution Approach 2:
The patent maintains a controlled inert atmosphere in the processing chamber after etching, preventing foreign substance formation by excluding reactive air components. This allows rapid processing without the harmful effects of air exposure, as the inert environment suppresses chemical reactions that would otherwise create adhesion-causing contaminants
3Length of moving object
If line width is reduced to form ultra-fine patterns, then circuit integration is improved, but patterns become more susceptible to foreign substance adhesion and collapse
Solution Approach 1:
The patent replaces mechanical contact-based cleaning methods with field-based thermal cleaning. By using thermal energy to decompose and remove foreign substances without physical contact, ultra-fine patterns with line widths of 32 nm or less are cleaned effectively without experiencing the mechanical stresses and surface tension forces that would cause collapse
Solution Approach 2:
The patent changes the temperature parameter to 160°C or higher during the cleaning process, which fundamentally alters the cleaning mechanism from liquid-based to thermal-based. This parameter change enables effective foreign substance removal while avoiding the physical contact issues that plague ultra-fine pattern processing, thereby maintaining pattern stability
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
Effectively recovers the shape of ultra-fine patterns by removing foreign substances, preventing adhesion and collapse, and ensuring the integrity of the silicon substrate during the process.
Implementation Method 1
heating the substrate to 160°C or higher, preferably between 200°C and 500°C
Implementation Method 2
foreign substances grown therein so that the patterns adjacent to each other are connected through the foreign substances
Implementation Method 3
there has been known a wet cleaning technique using a cleaning fluid including hydrogen fluoride
Implementation Method 4
there has been known a technique using mixed vapor of hydrogen fluoride and alcohol
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3
AI summary
A method for recovering a shape of patterns, formed on a silicon substrate by etching, by removing foreign substances grown between the patterns is provided. The method includes heating the silicon substrate accommodated in a chamber to a temperature of about 160°C or higher.