Supercritical Drying Apparatus with Radiant Particle Removal
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Solution Overview
Problem
Existing drying methods for semiconductor substrates, such as wet cleaning processes, often result in pattern collapse or adhesion due to surface tension, which supercritical drying aims to prevent by replacing cleaning solutions with supercritical fluids.
Innovation Solution
A supercritical drying apparatus comprising a drying chamber that uses a supercritical fluid, a chuck to hold the substrate, and a particle remover with radiant heat to decompose dry particles, along with gas supplies to manage pressure and prevent abrasion particle inflow, facilitating efficient drying without pattern collapse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wet cleaning processes are used to clean semiconductor substrates, then cleaning effectiveness is achieved, but pattern collapse or adhesion occurs due to surface tension
Solution Approach 1:
The patent changes the physical state of the cleaning fluid from liquid to supercritical fluid, fundamentally altering the parameters (pressure and temperature) to eliminate surface tension while maintaining cleaning effectiveness. The supercritical fluid achieves critical pressure (≥73 atm for CO2) and critical temperature (≥31°C for CO2) to transition into a state with liquid-like density but gas-like diffusivity and zero surface tension.
Solution Approach 2:
The patent utilizes phase transition of the cleaning fluid from liquid to supercritical state, and then to gas during drying. The substrate is exposed to supercritical CO2 which penetrates and cleans patterns, then the supercritical fluid is decompressed to gas phase for drying, avoiding the liquid-gas transition that causes surface tension and pattern collapse.
2Manufacturing precision
If supercritical fluid is used for drying, then pattern collapse is prevented, but dry particles remain on the substrate surface
Solution Approach 1:
The patent applies preliminary heating to the substrate before or during the supercritical drying process. By pre-heating the substrate to a temperature sufficient to volatilize residual cleaning solution (typically above the boiling point of the cleaning agent), the patent prevents the formation of dry particles during subsequent drying, while still benefiting from the zero surface tension of supercritical fluid.
3Object-generated harmful factors
If radiant heat is applied to remove dry particles, then particle removal is achieved, but energy consumption increases
Solution Approach 1:
The patent applies preliminary heating to the substrate before or during the supercritical drying process. By pre-heating the substrate to a temperature sufficient to volatilize residual cleaning solution (typically above the boiling point of the cleaning agent), the patent prevents the formation of dry particles during subsequent drying, thereby eliminating or reducing the need for additional radiant heat treatment and associated energy consumption.
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 apparatus effectively removes dry particles from semiconductor substrates using supercritical fluids and radiant heat, preventing pattern adhesion and ensuring precise drying without collapsing features.
Implementation Method 1
a drying chamber configured to receive a supercritical fluid and to dry a substrate
Implementation Method 2
a particle remover in the drying chamber, the particle remover being configured to remove dry particles from the substrate by heating the substrate with radiant heat
Data Source
AI summary
A supercritical drying apparatus and a method of drying a substrate, the apparatus including a drying chamber configured to receive a supercritical fluid and to dry a substrate; a chuck in the drying chamber, the chuck being configured to receive the substrate; and a particle remover in the drying chamber, the particle remover being configured to remove dry particles from the substrate by heating the substrate with radiant heat.