Multi-chamber Wafer Processing Apparatus with Supercritical Drying
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Solution Overview
Problem
The increasing number of tiers in NAND flash memory devices and reduced design rules lead to limitations in drying processes using isopropyl alcohol, necessitating the adoption of supercritical drying for pattern leaning issues, while existing supercritical drying apparatuses are often single-type and incapable of simultaneous wafer cleaning and drying processes.
Innovation Solution
A multi-chamber apparatus comprising a high etch rate chamber for silicon nitride etching with phosphoric acid, a rinse chamber for cleaning with an ammonia mixed solution, and a supercritical drying chamber for drying with a supercritical fluid, along with a robot arm system to facilitate sequential processing and prevent pattern leaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If isopropyl alcohol drying process is used, then the drying process is simple and fast, but pattern leaning occurs due to limitations with increased tiers and reduced design rules
Solution Approach 1:
The patent changes the physical state parameter of the drying medium from liquid (isopropyl alcohol) to supercritical fluid (CO2), which eliminates surface tension and prevents pattern leaning while maintaining efficient drying performance
Solution Approach 2:
The patent utilizes the phase transition properties of CO2 between supercritical and gas states to achieve drying without pattern leaning, where the supercritical to gas transition occurs without liquid surface tension that causes pattern leaning
2Device complexity
If a single-type supercritical drying apparatus is used, then the device structure is simple, but it cannot perform both wafer cleaning and drying processes simultaneously
Solution Approach 1:
The patent divides the processing system into separate functional chambers (cleaning chamber and drying chamber) that can operate independently and simultaneously, allowing both cleaning and drying processes to be performed on different wafers at the same time
Solution Approach 2:
The patent creates a multi-functional apparatus where each chamber can handle different processing tasks (cleaning with ammonia mixed solution, drying with supercritical CO2), and the robot arm system enables universal wafer transfer between chambers, making the system capable of performing multiple process types
3Reliability
If multiple separate apparatuses are used for cleaning and drying, then each apparatus can be optimized for its specific function, but the overall system complexity and space requirement increase
Solution Approach 1:
The patent combines multiple separate processing functions (cleaning and drying) into a single integrated apparatus with multiple chambers, maintaining the functional optimization of each process while reducing overall system complexity and space requirements through unified control and shared infrastructure
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 multi-chamber apparatus efficiently processes wafers by etching, cleaning, and drying in a sequential manner, improving process efficiency and preventing pattern leaning, thereby addressing the limitations of existing technologies.
Implementation Method 1
a high etch rate chamber to receive the wafer and to etch silicon nitride with a phosphoric acid solution
Implementation Method 2
a rinse chamber to receive the wafer and to clean the wafer with an ammonia mixed solution
Implementation Method 3
a supercritical drying chamber to dry the wafer with a supercritical fluid
Data Source
AI summary
A multi-chamber apparatus for processing a wafer, the apparatus including a high etch rate chamber to receive the wafer and to etch silicon nitride with a phosphoric acid solution; a rinse chamber to receive the wafer and to clean the wafer with an ammonia mixed solution; and a supercritical drying chamber to dry the wafer with a supercritical fluid.