EUV Dry Development Using Fluorination and Organic-Acid Cycles
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Solution Overview
Problem
There is a need for improved methods for developing photoresists, particularly for dry developing photoresists, to enhance development rates, resolution, and reduce line-edge roughness in microelectronic fabrication processes.
Innovation Solution
The method involves exposing a metal-oxo photoresist to a first treatment gas containing a fluorinating agent, followed by a second treatment gas with an organic acid, and alternating with purge gas cycles to thoroughly remove desired portions of the photoresist, thereby achieving higher resolution and lower line-edge roughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional wet development processes are used, then the photoresist can be removed, but the development rate is slow and line-edge roughness is high
Solution Approach 1:
The patent replaces the wet chemical development process with a dry thermal decomposition process using fluorinating agents. Instead of using liquid developers that cause swelling and rough edges, the invention uses gaseous CF4 or SF6 at elevated temperatures (200-400°C) to selectively remove exposed photoresist regions through fluorination reactions, achieving both high development rates and smooth line edges
Solution Approach 2:
The patent changes the physical and chemical parameters of the development process by using gaseous fluorinating agents at controlled temperatures (200-400°C) and pressures. The process parameters include gas flow rates, temperature profiles, and exposure times that are optimized to achieve complete photoresist removal while maintaining pattern fidelity and minimizing line-edge roughness
2Use of energy by moving object
If higher sensitivity photoresist materials are used, then less energy is required for development, but resolution and line-edge quality may be compromised
Solution Approach 1:
The patent applies local quality by using fluorinating agents that selectively react with exposed photoresist regions that have undergone chemical transformation during exposure. The fluorination reaction occurs preferentially in exposed areas where the photoresist chemistry has been modified, allowing selective removal while preserving unexposed regions and maintaining high resolution patterns
Solution Approach 2:
The patent replaces conventional chemical development with thermal fluorination, using heat-activated fluorinating agents to remove photoresist. This substitution enables precise control over the development process through temperature and gas flow parameters, achieving both high sensitivity (low energy requirement) and high resolution simultaneously
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 dry development process provides enhanced development rates, higher resolution, and lower line-edge roughness compared to traditional methods, effectively removing the desired portions of the photoresist and byproducts.
Implementation Method 1
exposing the workpiece to a first treatment gas containing a fluorinating agent during a first treatment process
Implementation Method 2
exposing the workpiece to a second treatment gas containing an organic acid during a second treatment process
Implementation Method 3
exposing the workpiece to a purge gas, and then ceasing the exposure of the workpiece of the purge gas
Data Source
AI summary
Embodiments of the present disclosure generally relate to methods for dry developing photoresists, such as metal-oxo photoresists. In one or more embodiments, a method of developing a photoresist is provided and includes exposing a workpiece containing a patterned metal-oxo photoresist disposed on a substrate to a first treatment gas containing a fluorinating agent during a first treatment process and ceasing the exposure of the workpiece of the first treatment gas. The method further includes exposing the workpiece to a second treatment gas containing an organic acid during a second treatment process, the second treatment process contains repeating a treatment cycle one or more times. The treatment cycles includes exposing the workpiece to the second treatment gas, ceasing the exposure of the workpiece of the second treatment gas, exposing the workpiece to a purge gas, and then ceasing the exposure of the workpiece of the purge gas.