Supercritical Fluid Drying Apparatus for Semiconductor Substrate Pattern Integrity
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Solution Overview
Problem
In semiconductor device manufacturing, the drying of substrates with fine patterns using supercritical processing fluids often results in pattern collapse due to premature evaporation of liquids within recesses before being replaced by the processing fluid.
Innovation Solution
A substrate processing apparatus and method that involves a processing container with a substrate holder, fluid supply units, and a controller to raise the pressure within the container to a supercritical state, ensuring that the processing fluid replaces the liquid in the recesses without causing evaporation, using a controlled circulation process to maintain the fluid in a supercritical state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a liquid within a recess of the pattern evaporates before being replaced with the processing fluid in the supercritical state, then the drying process can proceed, but pattern collapse occurs
Solution Approach 1:
The patent changes the physical parameters (pressure and temperature) of the processing fluid to achieve a supercritical state. By raising the pressure to supercritical levels before introducing the fluid, the system enables the fluid to penetrate and replace liquid in recesses without causing evaporation-induced pattern collapse, thus resolving the contradiction between drying efficiency and pattern integrity
Solution Approach 2:
The patent utilizes the phase transition of the processing fluid to supercritical state. The fluid transitions from liquid to supercritical phase through controlled pressure and temperature changes, allowing it to effectively replace liquid in pattern recesses while maintaining pattern integrity and enabling subsequent drying without collapse
2Reliability
If the pressure within the processing container is raised to supercritical state, then the processing fluid can replace liquid in recesses without evaporation, but the complexity of the processing apparatus increases
Solution Approach 1:
The patent applies preliminary action by raising the pressure to supercritical levels before the processing fluid contacts the substrate. This pre-conditioning of the fluid ensures that when it enters the recesses, it is already in the appropriate supercritical state to replace liquid without evaporation, thereby ensuring pattern integrity while managing apparatus complexity through staged processing
Solution Approach 2:
The patent replaces conventional thermal drying mechanisms with a pressure-based supercritical fluid system. Instead of using heat to evaporate liquid (which causes pattern collapse), the system uses pressurized supercritical fluid to physically displace and remove liquid, substituting a mechanical pressure-based approach for thermal 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
Prevents pattern collapse by ensuring that liquids within recesses are replaced by the processing fluid in a supercritical state, effectively preventing premature evaporation and maintaining the integrity of the substrate patterns during the drying process.
Implementation Method 1
a drying method using a processing fluid in a supercritical state
Implementation Method 2
a pressure raising process of supplying the pressurized processing fluid to the processing container so as to raise a pressure within the processing container to a processing pressure higher than a critical pressure of the processing fluid
Data Source
AI summary
A substrate processing apparatus performs: a pressure raising process of raising a pressure within the processing container to a processing pressure higher than a critical pressure of the processing fluid, after the substrate is accommodated in the processing container; and a circulation process of supplying the processing fluid to the processing container and discharging the processing fluid from the processing container while keeping a pressure at which the processing fluid is maintained in the supercritical state, within the processing container. In the pressure raising process, the supply of the processing fluid from the second fluid supply unit is stopped and the processing fluid is supplied from the first fluid supply unit into the processing container until at least the pressure within the processing container reaches the critical pressure. In the circulation process, the processing fluid is supplied into the processing container from the second fluid supply unit.