Wafer Drying Apparatus Preventing Ammonia Marks
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Solution Overview
Problem
The existing liquid processing methods using organic solvents for drying wafers after hydrofluoric acid processing can result in marks or watermarks due to the interaction of the wafer surface with ammonia components in the atmosphere, leading to unwanted reactions and surface damage.
Innovation Solution
A liquid processing apparatus and method that includes a removing mechanism to eliminate alkaline components from the processing environment before using an organic solvent for drying, utilizing a control system to manage the supply of hydrofluoric acid and organic solvent, and optionally employing a pressurizing mechanism or cleaning liquid jetting to prevent alkaline component invasion and ensure thorough removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wafer is dried by using an organic solvent after processing by hydrofluoric acid and ammonia component, then the wafer can be dried effectively, but marks such as watermarks may be generated on the wafer surface
Solution Approach 1:
The patent applies preliminary action by introducing a nitrogen atmosphere into the processing chamber before the drying step. This preliminary nitrogen introduction prevents ammonia components in the external atmosphere from contacting the wafer surface during subsequent drying with organic solvent, thereby preventing mark formation while maintaining effective drying
Solution Approach 2:
The patent uses nitrogen gas to create an inert atmosphere within the processing chamber during the drying process. This inert environment isolates the wafer from external ammonia components, preventing the chemical reactions that cause marks on the wafer surface while allowing the organic solvent to effectively dry the wafer
2Productivity
If the wafer surface is exposed to organic solvent with ammonia component present in outside atmosphere, then the drying process can proceed, but the wafer surface is attacked by ammonia component and organic solvent
Solution Approach 1:
The patent introduces nitrogen gas to create an inert atmosphere that prevents external ammonia components from entering the processing chamber during drying. This maintains high drying efficiency with organic solvent while eliminating surface attack caused by ammonia-solvent interaction
Solution Approach 2:
Nitrogen gas acts as an intermediary barrier between the external atmosphere containing ammonia and the wafer surface being dried. This intermediary prevents direct contact between harmful ammonia components and the wafer, allowing efficient drying to proceed without surface damage
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
Effectively prevents the generation of marks on the substrate by ensuring the removal of alkaline components before drying, thereby minimizing unnecessary reactions and ensuring a clean, mark-free surface, even when using hydrofluoric acid processing followed by organic solvent drying.
Implementation Method 1
a removing mechanism configured to remove an alkaline component in the casing
Implementation Method 2
an invasion preventing mechanism configured to prevent invasion of an alkaline component into the casing; preferably, the invasion preventing mechanism is formed of a pressurizing mechanism that increases an air pressure in the casing
Implementation Method 3
a drying-liquid supplying mechanism configured to supply an organic solvent for drying the substrate to be processed
Data Source
AI summary
A liquid processing apparatus 1 comprises a casing 5, a substrate holding mechanism 20 that holds a wafer (substrate to be processed) W, a process-liquid supplying mechanism 30 that supplies a process liquid, a draining cup 12 that receives a process liquid, and a draining pipe 13 that discharges a process liquid outside. The process-liquid supplying mechanism 30 includes a first chemical-liquid supply mechanism that supplies a hydrofluoric process liquid, and a drying-liquid supplying mechanism that supplies an organic solvent for drying a wafer W. A control part 50 causes the first chemical-liquid supplying mechanism to supply a hydrofluoric process liquid, and then causes the drying-liquid supplying mechanism to supply an organic solvent. In addition, before the control part 50 causes the drying-liquid supplying mechanism to supply an organic solvent, the control part causes a cleaning mechanism 10 to remove an alkaline component in a casing 5.