Supercritical Substrate Drying with Density-Matched Fluid Supply
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Solution Overview
Problem
In the manufacturing of semiconductor devices with stacked integrated circuits, pattern collapse during fine-pitch processing remains a challenge, and existing drying methods using supercritical processing fluids do not adequately address this issue.
Innovation Solution
A substrate processing apparatus and method that utilize a processing container with a first and second fluid ejector, supply lines with adjustable valves, and a density adjustment mechanism to control the flow and density of a processing fluid in a supercritical state, ensuring reliable suppression of pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single fluid ejector is used to supply processing fluid to the processing container, then the device complexity is reduced, but the manufacturing precision and reliability of pattern suppression deteriorate
Solution Approach 1:
The fluid supply system is segmented into two separate fluid ejectors (first and second fluid ejectors) with independent supply lines. Each ejector can operate independently to supply processing fluid at different stages, allowing precise control over the drying process to prevent pattern collapse while maintaining manageable system complexity
Solution Approach 2:
The first fluid ejector performs preliminary drying action by supplying processing fluid before the second fluid ejector activates. This staged approach ensures that initial drying requirements are met before transitioning to the second ejector, improving pattern suppression reliability without requiring both ejectors to operate simultaneously
2Productivity
If the processing fluid is supplied at high flow rate to reach supercritical state quickly, then the productivity is improved, but the manufacturing precision of pattern suppression deteriorates
Solution Approach 1:
The fluid supply is executed in periodic stages: first supply period with the first fluid ejector to gradually build pressure toward supercritical state, followed by a transition period with density adjustment, then second supply period with the second fluid ejector at high flow rate. This periodic action achieves supercritical state efficiently while preventing pattern collapse through controlled progression
Solution Approach 2:
The system changes operating parameters dynamically by switching between different fluid ejectors and adjusting their respective flow rates. The first ejector operates at lower flow rate during pressurization, then the system transitions to the second ejector operating at higher flow rate after supercritical state is achieved, optimizing both productivity and precision at different stages
3Productivity
If the density difference between supply line and container is large, then the fluid supply efficiency is improved, but the reliability of pattern suppression deteriorates
Solution Approach 1:
The density adjustment mechanism acts as a feedback control element that monitors and adjusts the density of processing fluid in the supply line before it enters the processing container. By reducing the density difference between supply line and container, it prevents sudden fluid injection that could cause pattern collapse, while still maintaining overall supply efficiency through the two-stage ejector system
Solution Approach 2:
The density adjustment mechanism serves as an intermediary between the high-pressure supply line and the processing container. It mediates the transition by adjusting fluid density to minimize shock effects, ensuring reliable pattern suppression while allowing efficient fluid transfer from the supply system to the processing environment
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 described solution effectively suppresses pattern collapse by carefully managing the pressure and flow rate of the processing fluid, ensuring reliable and efficient drying of semiconductor substrates.
Implementation Method 1
a processing container that process a substrate using a processing fluid in a supercritical state
Data Source
AI summary
A controller of a substrate processing apparatus executes: a first process in which a processing fluid is supplied to a processing container in a first period until a pressure in the processing container is increased and the processing fluid in the processing container reaches a supercritical state; a second process in which the processing fluid is supplied to the processing container at a flow rate larger than a flow rate of the processing fluid supplied to the first fluid ejector in the first process, in a second period; and a density adjustment process in which after ending of the first process and before starting of the second process, the density adjustment mechanism makes a difference between a density of the processing fluid present in the upstream region of a second opening/closing valve and a density of the processing fluid present in the processing container smaller than a predetermined threshold.