Metal-Containing Resist Development via Sequential Wet-Dry Processing
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Solution Overview
Problem
Existing substrate processing methods using extreme ultraviolet (EUV) light for photoresist exposure face challenges in effectively removing exposed and unexposed regions of metal-containing resist, leading to inefficiencies and potential pattern collapse during development.
Innovation Solution
A method involving sequential wet and dry development processes, including heating steps, to selectively remove regions of the metal-containing resist, followed by a curing process to stabilize the resist pattern and enhance its resistance to etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only wet development is used on metal-containing resist, then the development process is simple, but the selectivity and contrast of development are insufficient and pattern collapse occurs
Solution Approach 1:
The development process is segmented into two distinct stages: wet development followed by dry development. The wet development stage uses a liquid developer to initially remove exposed or unexposed resist regions, while the dry development stage uses a gaseous developer to complete the removal and enhance pattern definition. This segmentation allows each stage to perform its specialized function, improving overall development selectivity and contrast while preventing pattern collapse.
2Productivity
If conventional single development method is used, then the process is fast, but pattern collapse occurs during development
Solution Approach 1:
The wet development stage serves as a preliminary action that partially removes the resist material and prepares the pattern for the subsequent dry development stage. By performing this initial removal in a liquid environment, the structure is stabilized before the final dry development, preventing pattern collapse while maintaining overall process speed.
Solution Approach 2:
The invention changes the physical state parameter of the developer from liquid (wet development) to gas (dry development) between stages. This parameter change allows the process to leverage the solvating power of liquid developers for initial removal while using gaseous developers for final pattern definition, thereby maintaining productivity while improving pattern stability.
3Use of energy by moving object
If metal-containing resist is used for EUV exposure, then the resist absorbs EUV light effectively, but the removal of exposed and unexposed regions becomes difficult
Solution Approach 1:
The invention introduces a dual-development system where the wet developer acts as an intermediary that initially facilitates resist removal through liquid-phase chemical reactions. This is followed by a dry developer that completes the removal process. The intermediary wet development stage prepares the metal-containing resist for more effective removal in the subsequent dry stage, making the overall removal process easier despite the resist's high EUV absorption.
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 method improves the selectivity and contrast of development, reduces pattern collapse, and enhances the resistance of the resist pattern to etching, while maintaining precise dimensional control.
Implementation Method 1
a heating module configured to heat the substrate to a temperature between 50°C and 250°C
Data Source
AI summary
A substrate processing method includes: (a) performing wet development on a metal-containing resist of a substrate; and (b) performing dry development on the metal-containing resist, wherein the metal-containing resist includes an exposed first region and an unexposed second region, wherein in (a), one of the first region and the second region is partially removed in a thickness direction of the one of the first region and the second region, and wherein in (b), a remaining portion of the one of the first region and the second region is removed.