Plasma Wafer Thickness Detection with Unobstructed Optical Paths
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Solution Overview
Problem
Conventional plasma processing techniques face challenges in accurately detecting the remaining film thickness during the etching process, leading to reduced yield and increased variations in the wafer processing results due to obstructions in the light path and interference from gas introduction units and ion shielding plates.
Innovation Solution
A plasma processing apparatus with a configuration that includes a sample table, plasma formation chamber, introduction passage, heater, introduction plate with through-holes, and a detector to accurately measure the intensity of light or electromagnetic waves reflected from the wafer, allowing for precise detection of the remaining film thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gas introduction units and ion shielding plates are installed in the processing chamber, then plasma generation and ion control are improved, but light path obstruction and measurement accuracy deteriorate
Solution Approach 1:
The processing chamber is divided into distinct functional zones: a plasma generation region with gas introduction units and ion shielding plates, and a measurement region with unobstructed light paths. This spatial segmentation allows plasma components to perform their functions while preventing them from interfering with optical measurements of the remaining film thickness.
2Temperature
If heater and introduction plate are positioned to optimize heating, then heating efficiency is improved, but light path obstruction and detection accuracy deteriorate
Solution Approach 1:
The heater and introduction plate are designed with localized heating zones that concentrate thermal energy where needed on the wafer surface, while maintaining transparent or optically non-interfering structures in regions where light paths pass through. This allows efficient heating in specific areas without compromising overall measurement accuracy.
3Manufacturing precision
If detection system is added to measure remaining film thickness, then process control is improved, but device complexity increases
Solution Approach 1:
The detection system utilizes the existing heater structure as part of the optical measurement pathway, where the heater also serves as a reference element for detecting reflected light intensity changes. This multi-functional design allows the same component to contribute to both heating and measurement functions, reducing overall device complexity while maintaining precision process control.
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
This configuration enhances the accuracy of remaining film thickness detection, improving the yield and reducing variations in the wafer processing results by ensuring unobstructed light paths and minimizing interference.
Implementation Method 1
irradiates the wafer with light or electromagnetic waves for a heating step
Implementation Method 2
detects a change in intensity of the light or electromagnetic waves which are emitted from the heater and are reflected by the wafer
Implementation Method 3
plasma formation chamber which is arranged above the processing chamber inside the vacuum container and in which plasma is formed using a gas supplied therein
Implementation Method 4
an introduction passage which communicates the plasma formation chamber with the processing chamber, inside of which reactive particles in the plasma pass through to be introduced to an inside of the processing chamber
Data Source
AI summary
This invention provides a wafer processing method comprising a process of irradiating a wafer to be processed placed on the upper surface of a sample table arranged in a processing chamber with light or electromagnetic waves to heat and remove a compound layer of a film layer that is preliminarily formed on the upper surface of the film layer of the upper surface of the wafer, wherein in the process, by receiving the light or electromagnetic waves reflected by the upper surface of the wafer, a signal indicating a temporal change in intensity using the wavelength of the light or electromagnetic waves as a parameter is corrected using information of the intensity of the light or electromagnetic waves detected by receiving the light or electromagnetic waves at a position on the circumferential side of the upper surface of the sample table.