Supercritical CO2 Drying Apparatus for Wafer Pattern Collapse Prevention
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Solution Overview
Problem
In semiconductor manufacturing, existing drying methods using supercritical fluids face challenges in efficiently removing IPA from wafers without causing pattern collapse due to incomplete drying and pressure fluctuations.
Innovation Solution
A substrate processing apparatus and method that control the supply rate of supercritical CO2 to rapidly increase pressure within a processing container, ensuring complete IPA removal while maintaining the supercritical state, using a pump and controller to manage the fluid supply based on target time, pressure, and density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pressure increase is performed rapidly to improve productivity, then the drying efficiency is improved, but the pressure fluctuations may cause pattern collapse
Solution Approach 1:
The system performs preliminary calculation of the supply rate based on target pressure, container volume, and fluid density before initiating the pressure increase. This pre-planning ensures that the pressure rises smoothly and uniformly, avoiding sudden fluctuations that could cause pattern collapse while still achieving rapid drying.
Solution Approach 2:
The controller continuously monitors the actual pressure in the processing container and adjusts the supply rate dynamically to maintain the target pressure increase curve. This feedback mechanism prevents over-pressurization and ensures stable pressure conditions that protect the wafer pattern while achieving efficient drying.
2Loss of time
If the supply rate is increased to reduce processing time, then the productivity is improved, but the incomplete drying may occur due to pressure instability
Solution Approach 1:
The supply rate is dynamically adjusted during the pressure increase process rather than being fixed. The controller modifies the supply rate in real-time based on the actual pressure conditions, ensuring that the supercritical fluid is supplied at the optimal rate to achieve complete drying within the reduced processing time.
Solution Approach 2:
The system changes the supply rate parameter adaptively during the processing based on the target pressure increase curve. By adjusting this key parameter, the system ensures complete penetration of the supercritical fluid into the wafer structure for thorough drying while maintaining the reduced processing time.
3Manufacturing precision
If the amount of processing fluid is increased to ensure complete IPA removal, then the drying quality is improved, but the time required for pressure increase is extended
Solution Approach 1:
The system calculates the required amount of processing fluid in advance based on the target pressure and container volume. This preliminary calculation allows the system to supply the exact amount needed for complete IPA removal without over-supplying, which would extend the processing time unnecessarily.
Solution Approach 2:
The system replaces trial-and-error fluid supply methods with a calculation-based approach. By using the relationship between pressure, volume, and density to determine the required fluid amount, the system achieves complete drying with the precise amount of fluid needed, optimizing both quality and time.
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 effectively suppresses IPA evaporation and pattern collapse by ensuring thorough IPA dissolution and replacement with CO2, achieving efficient drying within a controlled timeframe.
Implementation Method 1
When a pressure increase is performed within the processing container by using the processing fluid
Implementation Method 2
a processing container configured to perform a supercritical fluid processing on a substrate with a processing fluid in a supercritical state
Implementation Method 3
ensuring complete IPA removal while maintaining the supercritical state, effectively suppresses IPA evaporation and pattern collapse by ensuring thorough IPA dissolution and replacement with CO2
Data Source
AI summary
A substrate processing apparatus includes a supercritical fluid producing apparatus including a pump configured to send out a processing fluid; a processing container configured to perform a supercritical fluid processing on a substrate with a processing fluid in a supercritical state sent from the supercritical fluid producing apparatus; and a controller configured to control at least the supercritical fluid producing apparatus. When a pressure increase is performed within the processing container by using the processing fluid, the controller determines a first supply rate at which the processing fluid is supplied to the processing container based on a target time during which the pressure increase is performed, an amount of the processing fluid required for the pressure increase and a density of the processing fluid. Further, the supercritical fluid producing apparatus supplies the processing fluid to the processing container based on the first supply rate.