Indirect Determination of Focus and Dose in Semiconductor Patterning
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Solution Overview
Problem
In semiconductor manufacturing, existing patterning processes face challenges in accurately measuring and controlling not directly measurable processing parameters such as focus and dose, which are crucial for producing consistent and defect-free patterns on substrates.
Innovation Solution
A method is developed to measure directly measurable parameters like critical dimensions (CDs) from substrate features, establish relationships with not directly measurable parameters like focus and dose, and use these relationships to determine the values of the latter, enabling precise control of the patterning process through a computer system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct measurement of processing parameters is performed, then measurement precision is improved, but the ability to measure not directly measurable parameters (focus, dose) deteriorates
Solution Approach 1:
The patent introduces an intermediary relationship model that connects directly measurable parameters (CD, LER, roughness) with not directly measurable parameters (focus, dose). This mediator enables indirect determination of focus and dose values through mathematical relationships, resolving the contradiction by allowing measurement of parameters that cannot be directly measured while maintaining measurement precision through the established relationships.
Solution Approach 2:
The patent replaces direct physical measurement mechanisms with a computational approach. Instead of attempting direct mechanical or physical measurement of focus and dose, the system uses computer-based calculations based on measured CD values and established relationships, substituting complex measurement mechanisms with simpler computational methods.
2Difficulty of detecting and measuring
If relationship-based indirect determination is used, then the ability to determine not directly measurable parameters is improved, but manufacturing precision may deteriorate due to additional processing steps
Solution Approach 1:
The patent applies preliminary action by pre-establishing relationships between directly measurable parameters and not directly measurable parameters before the actual measurement process. These relationships are determined in advance through calibration and modeling, allowing rapid and accurate indirect determination during production without adding complex real-time processing steps, thus maintaining manufacturing precision.
3Reliability
If multiple processing parameters are monitored, then process control is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by creating a multi-functional measurement and control system. The same measurement system that measures CD values serves multiple purposes: determining critical dimensions, calculating focus values, determining dose values, and monitoring process variations. This universal approach enables comprehensive process control without requiring separate dedicated systems for each parameter, thus avoiding increased device complexity.
Data Source
AI summary
A method including measuring a value of a directly measureable processing parameter of a patterning process from a portion of a substrate produced by the patterning process; obtaining a relationship between the directly measureable processing parameter and a not directly measureable processing parameter; and determining a value of the not directly measureable processing parameter from the value of the directly measureable processing parameter and the relationship.