Air-Knife Etching Pool for Semiconductor Material Removal
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Solution Overview
Problem
Conventional semiconductor manufacturing methods for removing undesired material, such as conductive seed layers or photoresist, are inefficient and costly, particularly due to the use of large etching baths and rolling seals that can damage substrates and require extensive capital investment.
Innovation Solution
A method utilizing air-knives to dispense and agitate an etching solution on a semiconductor substrate, forming a pool that moves across the substrate to remove material efficiently, reducing processing time and chemical usage while eliminating the need for immersion in large baths and rolling seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional large etching baths and rolling seals are used, then material removal can be achieved, but substrate damage occurs and capital investment is extensive
Solution Approach 1:
The patent segments the continuous etching bath into discrete droplets that are individually deposited and controlled on the substrate surface. This segmentation eliminates the need for complex rolling seals and large bath systems, reducing device complexity while maintaining effective material removal through controlled droplet exposure
Solution Approach 2:
The patent replaces the mechanical rolling seal system with a non-contact droplet deposition and removal mechanism. By using controlled liquid droplets that are deposited, processed, and evaporated/removed without mechanical contact, the system eliminates substrate damage from rolling seals while achieving the same etching function
2Productivity
If conventional immersion etching is used, then material removal is achieved, but processing time is long and chemical consumption is high
Solution Approach 1:
The patent employs periodic action by depositing etching solution in discrete droplets that are sequentially processed and removed. Each droplet undergoes a complete cycle of deposition, etching action, and evaporation/removal, allowing for rapid repeated cycles that increase material removal rate while using minimal chemical per unit area
Solution Approach 2:
The patent utilizes phase transitions by evaporating or rapidly removing the liquid etching droplets after brief contact with the substrate. This phase change from liquid to vapor (or rapid removal) enables quick turnover of the etching process, reducing processing time and allowing continuous high-speed material removal with minimal chemical consumption
3Ease of operation
If rolling seals are used for substrate handling, then substrate can be moved through etching solution, but substrate damage occurs
Solution Approach 1:
The patent replaces mechanical rolling seal handling with a non-contact droplet-based approach. The substrate is moved through zones where etching droplets are deposited and removed without mechanical contact, eliminating the harmful friction and pressure from rolling seals while maintaining ease of substrate transport through the etching process
Solution Approach 2:
The patent introduces air or controlled atmosphere as an intermediary medium between the substrate and etching solution. By using vapor-phase etching or controlled droplet evaporation in an air environment, the substrate can be handled and moved without direct contact with large volumes of liquid or mechanical sealing components, preventing damage while maintaining operational ease
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 approach significantly reduces processing time, chemical consumption, and maintenance costs, while maintaining process control and avoiding substrate damage, enabling faster and more efficient material removal with precise results.
Implementation Method 1
A first air-knife can be disposed over the conveyor and a second air-knife can be disposed over the conveyor and offset from the first air-knife by a distance D that is less than the length L of the semiconductor substrate
Implementation Method 2
A portion of the layer of material disposed between the first air-knife and the second air-knife can be etched with the pool of etching solution
Implementation Method 3
A portion of the layer of material disposed between the first air-knife and the second air-knife can be etched with the pool of etching solution
Implementation Method 4
The pool of etching solution and at least a portion of the layer of material etched by the pool of etching solution can be removed from the surface of the semiconductor substrate by moving the semiconductor substrate along the conveyor and past the second air-knife
Data Source
AI summary
A method of removing at least a portion of a layer of material from over a semiconductor substrate that can include dispensing an etching solution over the semiconductor substrate to form a pool of etching solution on the layer of material, wherein a footprint of the pool of etching solution is less than a footprint of the semiconductor substrate. The pool of etching solution and the semiconductor substrate can be moved with respect to each other. A pool boundary of the pool of etching solution can be defined on the semiconductor substrate with at least one air-knife such that the pool of etching solution etches the layer of material over the semiconductor substrate within the footprint of the pool of etching solution. The etching solution and at least a portion of the layer of material etched by the etching solution can be removed with the at least one air-knife.