Substrate Resistance Monitoring in Supercritical Fluid Drying
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Solution Overview
Problem
Existing methods for drying substrates using supercritical fluids struggle with accurately detecting process progress and solvent amount due to the difficulty in measuring organic solvents like isopropyl alcohol (IPA) during pressurization and depressurization, leading to potential pattern collapse in semiconductor manufacturing.
Innovation Solution
A substrate processing apparatus and method that utilizes a detector to measure resistance changes in the substrate, allowing real-time monitoring of process progress and solvent amount by comparing resistance values against predetermined thresholds, using a tray unit and detector connected to the substrate or lift pin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If temperature control is used in a state diagram of pressure and temperature, then the substrate can be dried using a supercritical fluid, but it is difficult to accurately detect process progress and solvent amount due to pressurization and depressurization
Solution Approach 1:
A tray unit is introduced as an intermediary component to enable resistance measurement of the substrate during the supercritical fluid drying process. The tray unit includes a tray supporting the substrate and a cover that seals the chamber opening, allowing the detector to measure substrate resistance without direct interference from the pressurization and depressurization of the supercritical fluid
Solution Approach 2:
The patent replaces direct mechanical measurement methods with electrical resistance measurement to detect substrate state. Instead of attempting to mechanically measure solvent amount or process progress under high pressure conditions, the system uses electrical resistance changes of the substrate as a proxy indicator, which can be measured accurately through the tray unit connection
2Device complexity
If conventional drying method using only temperature control is used, then the process is simple, but capillary force is generated at gas-liquid interface causing pattern collapse
Solution Approach 1:
The patent utilizes the phase transition properties of supercritical fluids to eliminate capillary force. By controlling pressure and temperature to maintain the fluid in a supercritical state (above critical point), the system avoids the gas-liquid interface that causes capillary action. The tray unit enables resistance monitoring throughout this phase-controlled drying process to ensure complete solvent removal without pattern collapse
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
Enables accurate detection of process completion and solvent removal, reducing the risk of pattern collapse and enhancing processing efficiency by ensuring optimal solvent application and timely process termination.
Implementation Method 1
a detector configured to measure a resistance of the substrate
Implementation Method 2
a processing method of drying the organic solvent using a fluid in a supercritical state (hereinafter referred to as 'supercritical fluid') that does not form an interface between gas or liquid
Implementation Method 3
The capillary force that causes the pattern collapse described above is due to the surface tension of the processing liquid that acts at a liquid/gas interface between the atmospheric atmosphere surrounding the substrate S after cleaning and the organic solvent between the patterns
Implementation Method 4
The capillary force that causes the pattern collapse described above is due to the surface tension of the processing liquid that acts at a liquid/gas interface
Data Source
AI summary
Provided is a substrate processing apparatus including a chamber providing a processing space in which a process is performed on a substrate coated with an organic solvent using a fluid in a supercritical state, a tray unit supporting the substrate and provided to be inserted into the chamber and withdraw from the chamber through an opening of the chamber, and a detector configured to measure a resistance of the substrate.