Supercritical CO2 Drying for Semiconductor Pattern Integrity
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Solution Overview
Problem
The fine patterns on semiconductor substrates tend to collapse or bend during the spin drying process in the photolithography developing process, known as the leaning phenomenon, which affects the precision and quality of semiconductor device manufacturing.
Innovation Solution
A substrate treating apparatus and method that utilizes a supercritical fluid treatment process, where a chamber is heated and controlled to supply and exhaust fluid simultaneously through top and bottom supply lines, ensuring the substrate is treated with heated fluid before and during the process, preventing the leaning phenomenon and effectively drying the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spin drying is performed using centrifugal force, then drying efficiency is improved, but pattern collapse or bending occurs
Solution Approach 1:
The patent changes the physical state parameter of the drying fluid from conventional liquid or gas to supercritical state. By controlling temperature and pressure parameters to achieve supercritical CO2, the drying process eliminates pattern collapse while maintaining high drying efficiency, as the supercritical fluid can penetrate and dry fine patterns without the mechanical stress of centrifugal force
Solution Approach 2:
The patent utilizes the phase transition characteristics of CO2 between supercritical and gaseous states. The CO2 is maintained in supercritical state during drying, then undergoes phase transition to gaseous state during decompression, leaving no residue and preventing pattern damage. This phase transition mechanism resolves the contradiction between drying efficiency and pattern integrity
2Productivity
If supercritical fluid is supplied to the chamber, then drying performance is improved, but temperature control becomes complex
Solution Approach 1:
The patent applies preliminary heating to the CO2 before it enters the chamber, and preliminary cooling to the chamber walls before supercritical fluid supply. This preliminary action ensures that when the supercritical CO2 contacts the substrate, the temperature conditions are already optimized, simplifying the overall temperature control system while maintaining high drying performance
Solution Approach 2:
The patent implements temperature sensors and control systems that monitor the actual temperature of the CO2 and chamber, providing feedback to adjust heating and cooling rates. This feedback mechanism simplifies temperature control by automatically maintaining optimal conditions without complex manual intervention
3Use of energy by moving object
If the chamber is heated before substrate introduction, then fluid heating efficiency is improved, but energy consumption increases
Solution Approach 1:
The patent heats the CO2 fluid and the chamber simultaneously before substrate introduction, but controls the heating to occur only in the necessary regions and times. The CO2 is heated to supercritical temperature, and the chamber is pre-heated to minimize thermal shock, but the heating is stopped or reduced when the substrate is introduced, avoiding unnecessary energy consumption while maintaining heating efficiency
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 prevents pattern collapse or bending, ensures precise drying of the substrate, and maintains substrate quality by using a supercritical fluid treatment that compensates for temperature variations and contaminants, enhancing the developing and cleaning processes.
Implementation Method 1
a heater installed on the supply line and configured to heat the treating fluid
Implementation Method 2
a substrate treating apparatus for compensating a temperature of a supercritical fluid supplied at a supercritical treating process
Implementation Method 3
a spin chuck supporting the substrate is rotated, and a spin drying is performed to dry a developing liquid or a rinsing liquid remaining on the substrate using a centrifugal force applied by the spin chuck to the substrate
Data Source
AI summary
The inventive concept provides a substrate treating apparatus. The substrate treating apparatus includes a chamber having a treating space therein; a supply line having a first open/close valve installed thereon and configured to supply a treating fluid to the treating space; a heater installed on the supply line and configured to heat the treating fluid; an exhaust line having a second open/close valve installed thereon and configured to exhaust the treating space; and, a controller configured to control the first open/close value and the second open/close valve such that the treating fluid heated is supplied to and exhausted from the treating space before a treating process is performed on a substrate in the treating space.