Multi-Chamber Optical Metrology With Beam Splitting and Intensity Control
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Solution Overview
Problem
Current optical metrology systems in semiconductor manufacturing face challenges such as variations in light beam intensity over time due to residue build-up on access windows, and increased manufacturing costs associated with sophisticated illumination systems.
Innovation Solution
An optical metrology system that utilizes a single light source and divides it into multiple beams, which are then adjusted using filter wheels to maintain consistent intensity, thereby reducing costs and accounting for changes in intensity without the need for multiple light sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple light sources are used to monitor multiple process chambers, then measurement reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent divides a single optical beam into multiple separate beams using beam splitters, with each beam directed to a different process chamber. This segmentation allows one light source to serve multiple chambers simultaneously, reducing the total number of light sources needed while maintaining monitoring capability across all chambers.
Solution Approach 2:
The single light source is designed to perform multiple functions by simultaneously illuminating multiple process chambers through beam division. Each chamber receives its own optical beam for independent monitoring, making the single light source universally applicable to all chambers rather than requiring dedicated sources for each.
2Measurement precision
If sophisticated illumination systems are used to maintain consistent light intensity, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent incorporates feedback mechanisms where the system continuously monitors the intensity of each optical beam and automatically adjusts parameters to maintain consistent illumination levels across all process chambers. This feedback control ensures measurement precision without requiring overly complex illumination systems.
Solution Approach 2:
The system maintains consistent light intensity by dynamically adjusting optical parameters such as beam splitter ratios, mirror positions, or filter selections rather than relying on complex illumination hardware. This approach achieves measurement precision through parameter optimization rather than system complexity.
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 effectively monitors and controls etch processes in multiple process chambers simultaneously, ensuring precise end-point detection and reducing manufacturing costs by eliminating the need for multiple expensive light sources.
Implementation Method 1
dividing the optical beam into a plurality of light beams
Implementation Method 2
reflecting one of the plurality of light beams off each of a plurality of calibration wafers to measure a property of each of the plurality of calibration wafers, each of the plurality of calibration wafers having a known surface reflectance
Data Source
AI summary
A method for monitoring a plurality of process chambers, the method includes generating an optical beam at a light source. The method further includes dividing the optical beam into a plurality of light beams. The method further includes providing the plurality of light beams to the plurality of process chambers. And the method further includes measuring the plurality of light beams after being reflected within the plurality of process chambers.