Parallel Reflecting Plates for Ion Neutralization in Semiconductor Fabrication
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Solution Overview
Problem
Existing semiconductor fabrication methods using plasma face challenges in ensuring uniformity during processes like etching due to charged particles causing amorphous layer transformation, chemical composition changes, and electrical damage, particularly when converting ions into neutral beams.
Innovation Solution
A substrate processing apparatus with a reflector comprising parallel or substantially parallel reflecting plates, each with a metal plate and an insulating layer, arranged obliquely to convert ions into neutral beams with the same directivity, using Coulomb repulsion to minimize collisions and reduce energy loss, thereby protecting the substrate from charge build-up and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If plasma is used for semiconductor fabrication processes, then deposition and etching can be performed, but the charged particles cause amorphous layer transformation, chemical composition changes, and electrical damage to the substrate
Solution Approach 1:
The patent converts the harmful charged plasma particles into beneficial neutral particles by introducing a neutralizing plate. The plate neutralizes the charge of incident ions through electron capture or recombination, transforming them into neutral atoms or molecules that can deposit or etch the substrate without causing charge-related damage such as amorphous layer transformation or electrical damage to sensitive structures.
Solution Approach 2:
The neutralizing plate serves as an intermediary component between the plasma source and the substrate. It intercepts charged particles from the plasma, neutralizes their charge, and releases them as neutral particles toward the substrate. This intermediary transformation eliminates the harmful effects of charged particles while preserving the useful chemical reactivity needed for fabrication processes.
2Object-affected harmful factors
If a neutralizing plate is used to convert ions into neutral beams, then substrate damage from charge build-up is reduced, but it becomes difficult to ensure process uniformity and etching uniformity
Solution Approach 1:
The patent employs a movable or adjustable neutralizing plate that can be dynamically repositioned during the fabrication process. This allows optimization of the neutralization zone position to achieve uniform particle distribution across the substrate surface. The dynamic adjustment capability enables maintenance of process uniformity while preserving the neutralization benefit.
Solution Approach 2:
The patent modifies operational parameters such as the angle of the neutralizing plate, its distance from the substrate, plasma density, and particle energy to optimize both neutralization effectiveness and process uniformity. By adjusting these parameters, the system achieves a balance between eliminating charge damage and maintaining consistent etching/deposition uniformity across the substrate.
3Speed
If the neutralizing plate is mounted at an adjustable angle to deflect ions, then ion direction can be controlled, but ensuring etching uniformity becomes increasingly difficult
Solution Approach 1:
The patent divides the neutralizing plate into multiple segmented sections or uses multiple plates arranged in an array. Each segment can be independently adjusted or positioned to control the deflection angle for different regions of the substrate. This segmentation allows customization of particle trajectories to achieve uniform etching across the entire substrate surface while maintaining precise directional control.
Solution Approach 2:
The patent employs asymmetric positioning or angling of the neutralizing plate relative to the substrate, where different sections of the plate are oriented at different angles to compensate for geometric effects and achieve uniform particle flux distribution. This asymmetric configuration optimizes both deflection control and etching uniformity by tailoring the particle incidence angles to the specific substrate geometry and process requirements.
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 solution enhances process uniformity and reduces substrate damage by converting ions into neutral beams with consistent directivity, improving the efficiency and accuracy of semiconductor fabrication processes while minimizing energy loss and heat generation.
Implementation Method 1
The incident ions may be incident on and reflected from the insulating layers of the reflecting plates by Coulomb repulsion without substantial collision
Data Source
AI summary
A substrate processing method may include forming a plasma; extracting ions from the plasma and accelerating the ions to have uniform or substantially uniform directivity using a grid system; irradiating the ions at a reflector, wherein the reflector includes a plurality of reflecting plates each having a metal plate and an insulating layer on the metal plate, wherein the reflecting plates are parallel or substantially parallel such that the insulating layers are exposed to the ions; reflecting the ions incident on the reflecting plates away from the insulating layers of the reflecting plates; colliding the ions reflected away from the insulating layers with the metal plates to convert the ions into neutral beams; and irradiating the neutral beams onto a substrate to process the substrate.