Supercritical Drying Apparatus Preventing Pattern Collapse
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Solution Overview
Problem
The spin dry method used in photolithography processes causes a leaning phenomenon where patterns on substrates collapse or bend due to reduced critical dimensions, leading to quality degradation and inefficiencies in substrate drying.
Innovation Solution
A substrate treating apparatus is designed with a developing chamber for supplying developing solutions, a supercritical chamber for treating substrates with supercritical fluids, and a transfer chamber with a controller to manage substrate transfer between these chambers, preventing drying and minimizing tact time, thereby addressing the leaning phenomenon.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the spin dry method is used to dry the substrate by rotating the spin chuck, then the substrate can be dried efficiently, but the patterns on the substrate collapse or bend due to centrifugal force
Solution Approach 1:
The patent replaces the mechanical spin dry method with a supercritical drying method. Instead of using centrifugal force from rotation, the substrate is transferred to a supercritical chamber where supercritical fluid (such as CO2) is used to remove remaining developing solution and rinse water, followed by controlled depressurization for drying. This substitution eliminates the mechanical stress that causes pattern collapse while achieving effective drying.
Solution Approach 2:
The patent utilizes phase transitions of supercritical fluid (typically CO2) to achieve drying. The supercritical fluid is introduced into the substrate, then the pressure is reduced below the critical point, causing the supercritical fluid to transition to gaseous phase. This phase change allows the fluid to escape from the substrate without causing mechanical stress, thereby preventing pattern collapse while effectively removing liquid residues.
2Productivity
If the substrate is transferred from the developing chamber to the spin dry chamber, then the developing process can be completed, but the substrate dries during transfer causing quality degradation
Solution Approach 1:
The patent implements continuous transfer of the substrate from the developing chamber directly to the supercritical drying chamber without intermediate drying steps. The substrate remains in a wet state throughout the transfer process, and the supercritical drying process begins immediately upon arrival at the drying chamber. This continuous action prevents unwanted drying during transfer while maintaining process efficiency.
Solution Approach 2:
The patent introduces a transfer chamber as an intermediary between the developing chamber and the supercritical drying chamber. This transfer chamber provides a controlled environment for substrate movement, preventing exposure to ambient air that would cause premature drying. The transfer chamber acts as a mediator that maintains the substrate in its wet state during the transition between processing steps.
3Manufacturing precision
If multiple processing steps are performed sequentially, then comprehensive substrate treatment is achieved, but the tact time for substrate transfer increases
Solution Approach 1:
The patent combines multiple processing functions into an integrated system where the developing chamber, transfer chamber, and supercritical drying chamber are connected in sequence. The substrate is processed continuously through these chambers without removal or intermediate handling. The merging of these functions into a single workflow eliminates transfer time losses that would occur with separate, discrete processing steps.
Solution Approach 2:
The patent prepares the substrate in advance by completing the developing process fully before initiating the transfer to the drying chamber. The developing solution is applied and processed completely beforehand, so that when the substrate enters the supercritical drying chamber, no additional processing steps are needed. This preliminary completion of the developing action minimizes the time required for subsequent transfer and drying operations.
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 efficiently performs developing, coating, and supercritical processes while preventing substrate drying during transfer, reducing pattern distortion and enhancing process efficiency by immediately transferring substrates with developing solutions to the supercritical chamber for drying.
Implementation Method 1
a supercritical chamber that treats the substrate by supplying a supercritical fluid
Implementation Method 2
a spin dry method of rotating a spin chuck that supports a substrate and drying a developing solution or a rinsing solution remaining on the substrate by using a centrifugal force exerted on the substrate by the spin chuck
Data Source
AI summary
An apparatus for treating a substrate includes a developing chamber that performs a developing process on the substrate by supplying a developing solution, a supercritical chamber that treats the substrate by supplying a supercritical fluid, and a transfer chamber having a transfer unit that transfers the substrate W between the developing chamber and the supercritical chamber.