Low-Energy Ion Beam Surface Cleaning for Damage-Sensitive Substrates
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current surface cleaning methods for semiconductors using plasma and ion sputtering systems often result in damage, such as increased surface roughness, stoichiometry changes, and crystal lattice damage, and are inefficient in removing organic impurities, especially at high temperatures and long process times.
Innovation Solution
A method utilizing a directed ion beam with a forming gas, such as argon and hydrogen, at low energies to remove impurities from semiconductor surfaces at room temperature or low temperatures, minimizing damage and achieving complete impurity removal without altering the substrate surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plasma systems or ion sputtering systems are used for surface cleaning, then impurities can be removed from the substrate surface, but the substrate surface suffers damage such as increased roughness, stoichiometry changes, and crystal lattice damage
Solution Approach 1:
The patent changes the energy parameter of the ion beam from high energy (conventional plasma/ion sputtering) to low energy (1-100 eV per ion), which fundamentally alters the interaction mechanism with the substrate surface. At these low energies, ions can remove impurities through chemical reactions and gentle physical sputtering without causing the damaging effects of high-energy ion bombardment such as lattice damage and excessive roughness
Solution Approach 2:
The patent introduces a forming gas (typically hydrogen or hydrogen-containing gas) as an intermediary medium. This gas serves multiple functions: it provides reactive species that chemically react with and remove organic impurities, it passivates the substrate surface to prevent damage, and it modifies the ion beam composition to be less damaging while maintaining cleaning effectiveness
2Manufacturing precision
If conventional plasma or ion sputtering methods are used, then surface cleaning can be achieved, but the process requires high temperatures and long processing times
Solution Approach 1:
The patent changes the temperature parameter from high temperatures (conventional plasma processing often requires 100-500°C) to low temperatures (near room temperature or slightly elevated temperatures up to 100°C). This is achieved by using low-energy ion beams that do not rely on thermal effects for impurity removal, instead using direct ion-impurity interactions and chemical reactions with the forming gas, dramatically reducing both temperature and process time requirements
3Productivity
If high energy ion beams are used for surface cleaning, then impurities can be removed, but the kinetic energy of ions causes substrate surface modification and damage
Solution Approach 1:
The patent fundamentally changes the ion beam energy parameter from high energy (keV range in conventional sputtering) to low energy (1-100 eV per ion). At these reduced energies, the ion beam maintains sufficient momentum to remove impurities through gentle sputtering and chemical reactions, while the kinetic energy is too low to cause significant substrate lattice damage, plastic deformation, or microstructure alteration that occurs with high-energy ion bombardment
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
The method effectively removes chemical impurities and surface oxides from semiconductors at low temperatures, reducing surface roughness and damage, enabling efficient and economical cleaning for subsequent processes like bonding without causing significant substrate modification.
Implementation Method 1
a first gas, in particular a forming gas, is ionized in an ion source and accelerated by an acceleration unit onto a point of a substrate surface
Implementation Method 2
The accelerated ions can loosen impurities from the substrate surface when the kinetic energy of the ions is greater than or at least as great as the bond energy between the impurity and the substrate surface
Implementation Method 3
a second gas, in particular a forming gas, is fed into the process chamber. The second gas serves to bind the detached impurities
Data Source
AI summary
A method for the surface treatment of a substrate surface of a substrate includes arranging the substrate surface in a process chamber, bombarding the substrate surface with an ion beam, generated by an ion beam source and aimed at the substrate surface, to remove impurities from the substrate surface, whereby the ion beam has a first component, and introducing a second component into the process chamber to bind the removed impurities. A device for the surface treatment of a substrate surface of a substrate includes a process chamber for receiving the substrate, an ion beam source for generating an ion beam that has a first component and is aimed at the substrate surface to remove impurities from the substrate surface, and means to introduce a second component into the process chamber to bind the removed impurities.