Resist Mixture Circulation Filtration for Defect Detection
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Solution Overview
Problem
The presence of defects such as bubbles, metallic particles, and other impurities in resist solutions used in semiconductor manufacturing leads to poor device geometry and reduced yield, necessitating effective filtration methods to remove these impurities.
Innovation Solution
A method involving the use of a mixing vessel, filters, and a predetermined solvent to dissolve and filter out cluster defects, followed by defect measurement using Flow Particle Tracking (FPT) and light scattering techniques to accurately detect and reduce impurities in the resist mixture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If circulation filtration is used to remove defects from resist, then defect removal effectiveness improves, but filtration time and process complexity increase
Solution Approach 1:
The patent applies preliminary action by performing defect removal filtration before resist coating. The resist is circulated through filters to remove particles and defects in advance, ensuring high cleanliness before the actual coating process. This preliminary filtration prevents defects from reaching the wafer during coating, achieving excellent defect removal effectiveness while optimizing process timing.
Solution Approach 2:
The patent uses an intermediary filtration system with multiple filter elements arranged in series. The resist flows through intermediate filtration stages that progressively remove different size ranges of particles. This intermediary filtration approach effectively removes defects without requiring excessive filtration time, as each filter stage targets specific particle sizes efficiently.
2Reliability
If multiple filter elements are used in series for filtration, then filtration effectiveness improves, but device complexity increases
Solution Approach 1:
The patent segments the filtration system into multiple filter elements with different pore sizes arranged in series. Each filter element targets specific particle size ranges, with larger pores handling bulk particle removal and smaller pores capturing finer particles. This segmentation achieves comprehensive filtration effectiveness while keeping each individual filter element relatively simple in design.
Solution Approach 2:
The patent applies local quality by assigning different pore sizes to different filter elements based on their specific filtration functions. The first filter element has larger pores for initial particle removal, while subsequent elements have progressively smaller pores for finer particle capture. This localized optimization of filter properties achieves high overall filtration effectiveness without uniformly increasing complexity across all filter stages.
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 effectively reduces impurities to a detectable limit, ensuring high-quality resist production by minimizing background scattered light and enabling precise defect detection, thereby improving semiconductor device yield.
Implementation Method 1
a process of applying a resist onto a semiconductor wafer (spin-coating device), by circulating filtration in which the resist is passed through a filter for a liquid
Implementation Method 2
measuring first defects of the first mixture; obtaining a second mixture by mixing the resist mixture and a predetermined first solution, the resist mixture being obtained from between the outlet and the mixing vessel; measuring second defects of the second mixture
Data Source
AI summary
A method of manufacturing a resist according to an embodiment includes obtaining a resist mixture by mixing a raw material of the resist in a mixing vessel; repeating delivering the resist mixture from a bottom of the mixing vessel to an inlet of a filter, the filter including the inlet and an outlet; filtering the resist mixture using the filter; and delivering the filtered resist mixture from the outlet to the mixing vessel; obtaining a first mixture by mixing the resist mixture and a predetermined first solution, the resist mixture being obtained from between the bottom and the inlet; measuring first defects of the first mixture; obtaining a second mixture by mixing the resist mixture and the predetermined first solution, the resist mixture being obtained from between the outlet and the mixing vessel; measuring second defects of the second mixture; and comparing the first defects and the second defects.