Metal-Containing Resist Baking With Reactive Gas for Pattern Fidelity
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Solution Overview
Problem
Conventional lithographic processes face challenges in achieving precise patterning and stability of metal-containing photoresists, particularly at advanced technology nodes like 16 nm, due to limitations in controlling bake ambient conditions and reactive gas introduction during post-application and post-exposure bakes.
Innovation Solution
A method involving controlled introduction of reactive gases such as water, oxygen, ozone, hydrogen peroxide, and ammonia during the bake process to promote cross-linking and removal of low molecular weight species in metal-containing photoresists, along with precise control of temperature and pressure, enhances the stability and pattern fidelity of EUV photoresists.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional bake processes are used for metal-containing photoresists, then the process is simple and fast, but the pattern fidelity and resist stability are insufficient at advanced technology nodes
Solution Approach 1:
The patent applies parameter changes by controlling multiple variables during the bake process including temperature profiles (ramp rates, hold temperatures), pressure conditions (atmospheric or vacuum), and reactive gas concentrations (oxygen, water vapor, ammonia at specific ppm levels). These parameter adjustments optimize cross-linking reactions in metal-containing photoresists to improve pattern fidelity at 16 nm and below while managing process complexity through systematic control.
Solution Approach 2:
The patent introduces reactive gases (oxygen, water vapor, ammonia) as intermediaries during the bake process. These gases mediate chemical reactions within the photoresist layer, promoting controlled cross-linking and removing low molecular weight species. The gases act as intermediaries that facilitate the desired chemical transformations without requiring direct mechanical or thermal intervention alone, thereby improving pattern fidelity.
2Stability of the object's composition
If reactive gases are introduced during bake to promote cross-linking, then resist stability improves, but process control complexity increases
Solution Approach 1:
The patent controls photoresist stability by adjusting reactive gas parameters including concentration levels (e.g., oxygen at 1-10% by volume, ammonia at 0.001-5% by volume), temperature (100-200°C ranges), and pressure conditions. These parameter changes optimize the chemical environment to promote cross-linking and remove volatile species, enhancing resist stability while managing the complexity of gas delivery through defined parameter ranges.
Solution Approach 2:
The patent implements feedback control by monitoring bake chamber conditions (temperature, pressure, gas composition) and adjusting reactive gas flow rates and concentrations accordingly. This feedback mechanism ensures optimal cross-linking occurs while preventing excessive complexity in the gas delivery system by using sensor-based control to maintain stable photoresist properties.
3Manufacturing precision
If vacuum conditions are used during bake, then removal of low molecular weight species improves, but equipment complexity and processing time increase
Solution Approach 1:
The patent utilizes phase transitions by employing vacuum conditions (reducing pressure to enhance volatilization) during the bake process. This phase transition approach facilitates the removal of low molecular weight species and volatile contaminants from the photoresist layer by lowering the boiling points and enhancing evaporation rates, thereby reducing defects and improving pattern fidelity.
Solution Approach 2:
The patent applies periodic action by implementing a multi-stage bake process that alternates between atmospheric and vacuum conditions, or uses stepped temperature profiles with vacuum applied at specific intervals. This periodic approach optimizes the removal of different types of volatile species at different stages, reducing overall processing time while maintaining defect reduction benefits.
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
This approach improves lithographic performance by stabilizing the photoresist, reducing defects, and expanding the process window for optimal cross-linking, thereby enhancing pattern fidelity and reducing contamination in high-volume manufacturing.
Implementation Method 1
exposing the substrate to the reactive gas species may promote cross-linking within the photoresist layer
Implementation Method 2
exposing the substrate to the reactive gas species may oxidize a metal hydride species in the photoresist layer to a metal hydroxide species
Implementation Method 3
exposing the substrate to the reactive gas species may promote removal of low molecular weight species in the photoresist layer
Implementation Method 4
exposing the substrate to the reactive gas species may promote removal of low molecular weight species in the photoresist layer
Data Source
AI summary
Various embodiments herein relate to methods, apparatus, and systems for baking metal-containing on a semiconductor substrate in the presence of a reactive gas species. For example, the method may include receiving the substrate in a process chamber, the substrate having a photoresist layer thereon, where the photoresist layer includes a metal-containing photoresist material; flowing a reactive gas species from a gas source, through a gas delivery line, into the process chamber, and exposing the substrate to the reactive gas species in the process chamber; and baking the photoresist layer while the substrate is exposed to the reactive gas species.