Optical Bundle Endpoint Detection for Low-Loss Spectral Metrology
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Solution Overview
Problem
Conventional endpoint detection systems in manufacturing microelectronics are inadequate for precise and efficient spectral data collection, leading to substandard devices due to under-processing or over-processing, which is exacerbated by increasing demands for quality and uniformity in semiconductor devices.
Innovation Solution
An endpoint detection system utilizing an optical bundle with paired emitting and receiving optical fibers and an achromatic lens to collect and analyze reflected spectral components from multiple portions of a substrate surface, providing enhanced spectral data collection without signal loss, ensuring accurate determination of the substrate's state during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional endpoint detection systems are used for spectral data collection, then device manufacturing can proceed, but measurement precision and spectral data quality deteriorate due to signal loss and inadequate detection capability
Solution Approach 1:
The optical bundle is segmented into multiple individual optical fibers (e.g., 19 fibers arranged in a circular pattern) rather than using a single conventional detection path. This segmentation allows multiple light beams to illuminate different portions of the substrate surface simultaneously, collecting spectral data from multiple locations and improving overall measurement precision while maintaining signal integrity through redundant detection paths
Solution Approach 2:
The system transitions from single-point or line-based spectral detection to area-based spectral detection by arranging optical fibers in a two-dimensional circular pattern. This dimensional change enables simultaneous collection of spectral data from multiple substrate locations, enhancing measurement precision and providing comprehensive surface characterization without signal loss
2Manufacturing precision
If conventional optical detection systems are used, then device manufacturing can proceed, but manufacturing precision deteriorates due to inadequate endpoint detection capability
Solution Approach 1:
The optical bundle with multiple fibers serves multiple functions simultaneously: it acts as both the illumination source array and the detection array, with each fiber pair (emitting and receiving) functioning as an independent measurement channel. This multi-functionality improves endpoint detection accuracy by capturing spectral information from multiple substrate portions while avoiding the complexity of separate illumination and detection systems
Solution Approach 2:
The emitting and receiving optical fibers are merged into a single integrated optical bundle assembly, with fibers positioned in alternating pattern (emitting, receiving, emitting, receiving). This merging simplifies the overall system configuration compared to using separate illumination and detection systems, while maintaining high manufacturing precision through coordinated multi-point spectral measurement
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 system enables more accurate measurement of substrate profiles, allowing for precise endpoint detection and improved process control, reducing signal loss and enhancing the quality and uniformity of microelectronic devices.
Implementation Method 1
The achromatic lens is configured to responsive to receiving a first light beam of the incident light from the first emitting optical fiber, direct a first set of spectral components of the first light beam to a first portion of a substrate surface. The achromatic lens is further configured to direct a second set of spectral components of the first light beam to a second portion of the substrate surface.
Implementation Method 2
The optical bundle includes a first set of optical fibers including a first emitting optical fiber and a first receiving optical fiber. The first emitting optical fiber is disposed at a pairing angle relative to the first receiving optical fiber. The first emitting optical fiber and the second emitting optical fiber are configured to receive the incident light from the light source.
Implementation Method 3
The achromatic lens is further configured to collect a first set of reflected spectral components of light and a second set of reflected spectral components of light from the substrate surface. The set of reflected spectral components of light is produced by the first set of spectral components directed onto the first portion of the substrate surface.
Data Source
AI summary
Spectral data associated with a current operation of a current process performed with respect to a current substrate at a manufacturing system is received during the current process. Spectral data associated with a prior operation of the current process is identified. A difference between the spectral data associated with the current operation and the spectral data associated with the prior operation is determined. A metrology measurement value associated with the current substrate is updated based on the determined difference between the spectral data associated with the current operation and the spectral data associated with the prior operation of.