Wafer Etch Status Detection Using Multi-Chamber Reflectance
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Solution Overview
Problem
Conventional etching processes in semiconductor manufacturing require off-line measurements to determine their status, leading to inefficiencies and resource wastage when failures are detected only after subsequent processes have been completed.
Innovation Solution
Implementing a multi-chamber system with integrated optical reflectometers for real-time, multi-wavelength reflectance measurements to immediately assess the etching process status, using a broadband light source and processor for accurate material identification and generating activation signals based on reflectance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If off-line measurement is performed to determine etching process status, then measurement simplicity is maintained, but productivity deteriorates due to delayed detection and resource wastage
Solution Approach 1:
The patent implements real-time reflectance measurement during the etching process itself, rather than performing measurements after the process completes. The optical measurement system is integrated into the etching chamber, allowing the wafer's reflectance to be monitored continuously as etching occurs. This enables immediate detection of process status and material removal completion, eliminating the time loss associated with post-process offline measurements.
2Measurement precision
If multi-wavelength reflectance measurement is implemented, then measurement precision improves for material identification, but device complexity increases
Solution Approach 1:
The patent utilizes multi-wavelength (broadband) light to measure reflectance at multiple wavelengths simultaneously. Different materials exhibit characteristic reflectance spectra across the wavelength range, allowing precise material identification and thickness measurement. The system compares measured reflectance spectra with simulated spectra for various materials and thicknesses to determine the etching status with high precision, despite the increased complexity of the optical system.
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
Enables immediate detection of etching process success or failure, reducing waste and improving efficiency by preventing further processing of defective wafers, with enhanced sensitivity and accuracy through multi-wavelength reflectance analysis.
Implementation Method 1
performing reflectance measurements to the wafer in the factory interface, the load lock chamber, the buffer chamber
Implementation Method 2
using a broadband light source and processor for accurate material identification
Data Source
AI summary
A method includes: transferring a wafer from a factory interface through a load lock chamber to a buffer chamber; transferring the wafer from the buffer chamber to a process chamber; etching the wafer in the process chamber, to remove a material of the wafer; and after the wafer is etched, performing reflectance measurements to the wafer in the factory interface, the load lock chamber, the buffer chamber, or combination thereof, to identify if the material of the wafer is removed entirely according to a reflectance of the wafer.