Gas Phase Cleaning for Semiconductor Conductive Patterns
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to issues such as decreased electric characteristics and operation defects due to the generation of conductive residues, which are difficult to remove using existing methods, especially between conductive layer patterns with narrow line widths and spaces.
Innovation Solution
A gas phase cleaning process using a cleaning gas containing elements like chlorine and silicon to react with metal residues, forming volatile metal compounds that are evaporated, along with the formation of an insulating interface layer to remove residues and prevent leakage currents, while maintaining the integrity of the conductive layer patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If physical size of device structures is decreased to achieve higher integration, then device density increases, but electric characteristics deteriorate and operation defects occur due to conductive residues
Solution Approach 1:
The patent changes the chemical parameters of the cleaning process by introducing a two-stage gas phase cleaning method. The first stage uses a metal-reactive gas to form volatile metal compounds, and the second stage uses an oxidizing gas to remove organic residues. This parameter change enables effective residue removal at nanometer-scale dimensions without damaging the conductive layer patterns, thereby maintaining electric characteristics while achieving higher integration density.
Solution Approach 2:
The patent introduces cleaning gases as intermediary substances that mediate between the conductive residues and the removal process. The first cleaning gas (reactive to metal) and second cleaning gas (oxidizing) act as intermediaries that selectively remove residues through chemical reactions, enabling precise control over the cleaning process without direct mechanical or thermal damage to the miniaturized structures.
2Ease of manufacture
If conventional cleaning methods are used to remove residues, then some residue removal is achieved, but conductive residues between narrow line width patterns remain and cause leakage currents
Solution Approach 1:
The patent segments the residue removal process into two distinct stages: first removing metal-containing residues through reaction with a metal-reactive gas, then removing organic residues through oxidation. This segmentation allows each stage to target specific residue types selectively, ensuring complete removal of all conductive residues between narrow line width patterns without causing leakage currents.
Solution Approach 2:
The patent replaces conventional mechanical or thermal cleaning methods with a chemical-based gas phase cleaning process. The cleaning gases chemically react with and transform the residues into volatile compounds that can be removed without mechanical contact, thereby avoiding damage to the narrow conductive patterns and preventing leakage current generation.
3Manufacturing precision
If aggressive cleaning processes are used to remove all residues, then residue removal is improved, but damage to conductive layer patterns occurs
Solution Approach 1:
The patent applies local quality by using cleaning gases with different chemical specificities at different stages. The first cleaning gas is specifically reactive to metal residues, while the second cleaning gas targets organic residues. This localized chemical specificity ensures complete residue removal while the selective nature of each gas prevents damage to the conductive layer patterns, maintaining their structural integrity.
Solution Approach 2:
The patent implements continuous useful action through a sequential two-stage cleaning process where the first stage removes metal residues and the second stage removes organic residues. This continuous, multi-stage approach ensures complete residue removal without requiring aggressive single-stage cleaning that would damage the conductive patterns, thereby maintaining manufacturing precision while preserving pattern strength.
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 reduces leakage currents and improves the electric properties of semiconductor devices by selectively removing conductive residues without damaging the conductive layer patterns, enhancing the reliability of highly integrated semiconductor devices like DRAM and flash memory.
Implementation Method 1
The volatile metal compound is evaporated to remove the metal component in the residue
Implementation Method 2
The cleaning gas contains an element to react with the metal element and generating a volatile metal compound
Implementation Method 3
oxygen and the silicon contained in the cleaning gas may react to form silicon oxide on the substrate
Implementation Method 4
a surface portion of the substrate through a reaction of a portion of the cleaning gas and oxygen
Data Source
AI summary
Methods of forming conductive patterns include forming a conductive layer including a metal element on a substrate. The conductive layer is partially etched to generate a residue including an oxide of the metal element and to form a plurality of separately formed conductive layer patterns. A cleaning gas is inflowed onto the substrate including the conductive layer pattern. The metal compound is evaporated to remove the metal element contained in the residue and to form an insulating interface layer on the conductive layer pattern and a surface portion of the substrate through a reaction of a portion of the cleaning gas and oxygen. The residue may be removed from the conductive layer pattern to suppress generation of a leakage current.