Wafer Drying Negative Pressure Chamber Prevents Pattern Collapse
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Solution Overview
Problem
Pattern collapse during drying of semiconductor wafers is a significant issue in the production of DRAM, leading to reduced yield due to increased depth-to-width ratios of semiconductor integrated circuits.
Innovation Solution
An apparatus and method that utilize a negative pressure chamber and vacuum pump to reduce the surface pressure of a drying agent, such as Isopropyl Alcohol, by creating a negative pressure environment, thereby reducing the boiling point and surface tension, which minimizes capillary forces and prevents pattern collapse during the drying process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a drying agent is sprayed onto the wafer at atmospheric pressure, then the drying process is simple and fast, but the high surface pressure causes pattern collapse due to capillary forces
Solution Approach 1:
The patent changes the pressure parameter of the drying agent from atmospheric pressure to negative pressure (vacuum). By reducing the pressure in the chamber containing the wafer, the boiling point of the drying agent is lowered and surface tension is reduced, which minimizes capillary forces that cause pattern collapse while maintaining efficient drying.
Solution Approach 2:
The patent utilizes phase transition of the drying agent from liquid to vapor more efficiently under negative pressure conditions. The reduced pressure environment accelerates the evaporation process and allows the drying agent to transition to vapor phase more readily, preventing liquid-phase capillary forces from damaging the pattern while maintaining high drying efficiency.
2Productivity
If the drying agent has high surface tension for effective drying, then drying efficiency is improved, but capillary forces increase causing pattern collapse
Solution Approach 1:
The patent changes the pressure parameter of the environment to negative pressure, which fundamentally alters the behavior of the drying agent. Under negative pressure, the surface tension of the drying agent is reduced, which decreases capillary forces that cause pattern collapse, while the drying efficiency is maintained or improved due to enhanced evaporation rates in the vacuum environment.
Solution Approach 2:
By creating a negative pressure environment, the patent promotes faster phase transition from liquid to vapor. This reduces the time the drying agent remains in liquid form on the wafer surface, thereby minimizing the duration of capillary force exposure while maintaining effective drying through accelerated evaporation.
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 effectively reduces the probability of pattern collapse, improving the yield of wafer processing by ensuring the drying agent vaporizes easily and evenly, thus maintaining the integrity of the wafer patterns.
Implementation Method 1
a gas in the negative pressure chamber is sucked by the vacuum pump through the pipeline to generate a negative pressure in the first chamber
Implementation Method 2
reduce the boiling point and surface tension, which minimizes capillary forces and prevents pattern collapse during the drying process
Data Source
AI summary
An apparatus for processing a wafer is provided. The provided apparatus for processing a wafer includes a chamber, a first nozzle, a negative pressure chamber and a vacuum pump. The first nozzle is arranged in the chamber and configured to spray a drying agent to the wafer. The negative pressure chamber is located in the chamber. The vacuum pump is located outside of the chamber and connected with the negative pressure chamber through a pipeline. The negative pressure chamber is arranged in a direction perpendicular to the wafer, and a gas in the negative pressure chamber is sucked by the vacuum pump through the pipeline to generate a negative pressure in the chamber, so as to reduce a surface pressure of the drying agent sprayed onto the wafer by the first nozzle. A method for controlling processing of a wafer is also provided.