EUV Photoresist Pattern Quality via Multi-Stage Baking and Development
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Solution Overview
Problem
In semiconductor device manufacturing, the photolithography process faces challenges in achieving improved photoresist pattern quality, particularly with the increasing use of extreme ultraviolet (EUV) wavelengths, where existing methods struggle to refine line widths and intervals effectively.
Innovation Solution
A substrate processing method involving multiple post-exposure baking processes and developing steps with different temperature solutions is employed, including a first and second post-exposure baking process, and a hard baking process, to enhance photoresist pattern formation and quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single post-exposure baking process and single temperature developing solution are used, then the process is simple, but the photoresist pattern quality and adhesion are insufficient for advanced EUV lithography
Solution Approach 1:
The patent divides the post-exposure baking process into multiple stages (first PEB at 90-110°C for 30-60 seconds, second PEB at 110-130°C for 30-60 seconds) and the developing process into multiple temperature stages (first developing at 20-30°C, second developing at 40-60°C). This segmentation allows each stage to perform specific functions: the first PEB and developing establish basic pattern formation, while the second PEB and developing refine the pattern quality and adhesion. This resolves the contradiction by breaking down a complex quality improvement goal into manageable sequential steps.
Solution Approach 2:
The patent systematically changes temperature parameters throughout the process: starting with moderate temperature PEB and developing, then progressing to higher temperature PEB and developing. This parameter progression optimizes the photoresist properties at each stage - lower temperatures preserve pattern fidelity while higher temperatures enhance adhesion and durability. This resolves the contradiction by using controlled parameter variations to achieve quality improvement without requiring entirely new process equipment.
2Manufacturing precision
If multiple post-exposure baking and developing steps are used, then photoresist pattern quality improves, but processing time increases
Solution Approach 1:
The patent implements periodic action through alternating cycles of PEB and developing steps. Each cycle consists of a PEB step followed by a developing step, creating a rhythmic process pattern. This periodic structure allows the photoresist to undergo repeated cycles of chemical modification and pattern formation, progressively improving quality. The regular timing and temperature control of each periodic cycle ensures that quality enhancement is achieved efficiently without excessive time consumption.
Solution Approach 2:
The first PEB and developing steps perform preliminary pattern formation and stabilization before the second PEB and developing steps refine the quality. This preliminary action establishes a solid foundation that reduces the time required for subsequent refinement steps. By preparing the photoresist in advance with appropriate chemical modifications and pattern definition, the later high-temperature steps can focus specifically on adhesion and durability enhancement without needing to perform basic pattern formation, thus reducing total processing time.
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 method improves photoresist pattern quality by controlling temperature variations during development, leading to better adhesion, durability, and refined pattern formation suitable for advanced EUV lithography.
Implementation Method 1
a heater configured to apply heat to at least one from among the tank, the liquid supply unit, and the substrate
Implementation Method 2
performing a first post-exposure baking process on the photoresist layer; performing a second post-exposure baking process on the photoresist layer
Data Source
AI summary
A substrate processing method includes: performing a first post-exposure baking process on a photoresist layer that was previously exposed to for extreme ultraviolet (EUV) exposed to EUV; developing the photoresist layer using a first developing solution having a first temperature; performing a second post-exposure baking process on the photoresist layer; developing the photoresist layer using a second developing solution having a second temperature, higher than the first temperature; and forming a photoresist pattern by performing a hard baking process on the photoresist layer.