Edge Zone Coating Removal Using Angled Etchant and Gas Shrouds
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Solution Overview
Problem
Current methods for removing coatings from substrate edges in semiconductor fabrication are inefficient, often requiring multiple passes, leading to debris redeposition, edge irregularities, and risk of panel breakage, especially with thinner substrates, and are costly and hazardous.
Innovation Solution
An apparatus and method using a vacuum chuck assembly and nozzle assembly with angled liquid streams and gas shrouds to simultaneously remove coatings from both sides of a substrate edge, ensuring a straight and clean edge with minimal debris.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser or plasma ablation is used to remove coating from substrate edge, then coating removal can be achieved, but multiple passes are required and debris redeposition occurs
Solution Approach 1:
The patent replaces mechanical/thermal ablation methods (laser, plasma) with a chemical etching approach using liquid etchant delivered through a controlled spray system. This substitution eliminates the need for multiple passes and prevents debris redeposition by using chemistry rather than mechanical removal.
Solution Approach 2:
The patent changes the fundamental mechanism from physical/thermal removal to chemical removal. By using liquid etchant spray with controlled parameters (flow rate, spray angle, gas shroud pressure), the process achieves complete coating removal in a single pass without the drawbacks of repeated ablation passes.
2Manufacturing precision
If laser or plasma ablation is used to remove coating from substrate edge, then coating removal can be achieved, but edge irregularities and defects result
Solution Approach 1:
The patent applies local quality by directing the liquid etchant spray at a specific angled orientation (30-60 degrees) relative to the substrate surface. This controlled angle ensures uniform chemical etching across the edge zone, producing straight edges without the irregularities caused by isotropic laser or plasma ablation.
Solution Approach 2:
The patent introduces a gas shroud as an intermediary between the liquid etchant and the environment. The gas shroud contains the etching process, preventing debris scattering and redeposition, while the liquid etchant acts as a controlled mediator that chemically removes coating material uniformly, resulting in straight edges.
3Manufacturing precision
If traditional laser coating removal is used on thinner substrates, then coating removal can be achieved, but panel breakage risk increases
Solution Approach 1:
The patent replaces high-energy thermal/mechanical laser ablation with low-energy chemical etching using liquid spray. This substitution dramatically reduces the energy input to the substrate, eliminating the risk of thermal damage or mechanical stress that could cause breakage in thin substrates while maintaining effective coating removal.
Solution Approach 2:
The patent changes the energy delivery mechanism from high-energy density laser to low-energy density liquid spray. By controlling spray parameters (flow rate, pressure, angle) rather than using high-power laser, the process removes coating effectively without concentrating excessive energy that could fracture thin substrates.
4Manufacturing precision
If laser or plasma ablation is used to remove coating, then coating removal can be achieved, but expensive equipment and ventilation systems are required
Solution Approach 1:
The patent replaces expensive, complex, and hazardous ablation equipment (laser systems, plasma generators, requiring specialized ventilation and safety systems) with a simpler, more affordable liquid spray delivery system. The equipment is less costly, easier to operate, and eliminates the need for complex safety infrastructure while maintaining coating removal capability.
5Manufacturing precision
If multiple passes of laser or plasma ablation are used, then coating removal can be achieved, but debris redeposition on coated surfaces occurs
Solution Approach 1:
The patent introduces a gas shroud as an intermediary barrier between the liquid etchant spray and the surrounding environment. This gas shroud contains the chemical etching process, preventing generated debris from scattering and redepositing on the substrate surface, while allowing complete coating removal through controlled liquid delivery.
Solution Approach 2:
The patent replaces mechanical ablation (laser/plasma) that generates debris-prone physical removal with chemical etching using liquid spray. This substitution inherently prevents debris redeposition because chemical dissolution produces soluble or controllable byproducts rather than particulate debris that can redistribute.
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
Achieves efficient and controlled coating removal with reduced edge irregularities and debris, suitable for thinner substrates, while minimizing the need for additional cleaning and reducing the risk of panel breakage.
Implementation Method 1
The vacuum chuck assembly may include a plurality of vacuum cups configured to hold the substrate using suction
Implementation Method 2
A pair of nozzle tips is supported on the body and positioned on opposite sides of the cavity. The pair of nozzle tips may each be inclined towards the suction cup and configured to direct an angled stream of a liquid on a surface of the substrate received in the cavity
Implementation Method 3
An annular duct may be defined around each nozzle tip of the pair of nozzle tips. The annular duct may be configured to discharge a pressurized gas to form a gas shroud around the angled stream of liquid
Data Source
AI summary
An apparatus to remove a coating from an edge of a substrate includes a vacuum chuck assembly and a nozzle assembly. The vacuum chuck assembly is configured to support the substrate using suction. The nozzle assembly includes a nozzle head with a pair of nozzle tips configured to direct an angled liquid stream on a surface of the substrate. An annular duct around each nozzle tip discharges a pressurized gas to form a gas shroud around the angled liquid stream.